ENGINEERING  LIBRARY 


X 

N 


AIDS 


TO 


Engineers1  Examinations 


QUESTIONS  AND  ANSWERS. 


/ 


\ 


COPYRIGHT  BY 

THEO.  AUDEL  &  CO.,  NEW  YORK  CITY. 
SEPT.,  1894  AND  SEPT.,  1901 


V 


/ 


\ 


THIS  WORK  is  DEDICATED  TO 
VICTOR  HAWKINS 

AT  WHOSE  REQUEST   IT  HAS  BEEN   COMPILED 


\ 


WASHINGTON   MTTLLIN. 
See  page  203. 


\ 


X 


A 


TO 


ENGINEERS'  EXAMINATIONS. 

PREPARED    FOR 

APPLICANTS  OF  ALL  GRADES, 

WITH 

QUESTIONS  AND  ANSWERS. 

A  Summary  of  the  Principles  and  Practice 
of  Steam  Engineering*  V 


BY   N.  HAWKINS,    M.    E., 
//   ' 

Author:  New  Catechism  of  the  Steam  Engine:  Hand  Book 

of  Calculations  for  Engineers;  Instructions  for  the 

Boiler  Room  ;  New  Catechism  of  Electricity,  etc. 


NEW  YORK: 
THEO.  AUDEL  &  Co.,        63  FIFTH 


1903. 


\ 


/ 


ENGINEERJWG  LIBRARY 


\ 


*^ 


INTRODUCTION. 


There  are  three  parties  to  an  engineer's  license  : 

FIRST.     The  Applicant. 

SECOND.    The  Public. 

THIRD.     The  Examiners,  or  examining  board  of  engineers. 

To  the  applicant  the  period  of  an  examination  is  a  season 
of  nervous  dread,  and  the  utmost  fitness  does  not  always 
remove  the  feeling  of  anxiety. 

Men  often  operate  steam  plants  satisfactorily  who  can- 
not tell  how  they  do  it,  and  a  thoroughly  practical  engineer 
may  make  a  very  poor  showing  when  questioned  by  an 
examiner. 

It  is  sometimes  still  worse  when  modest  applicants 
are  required  to  write  their  experience,  for  in  the  hands  of 
many  men  the  pen  is  an  awkward  tool  ;  hence,  a  very  large 
margin  is  allowed  to  men  who  can  demonstrate  that  they 
have  had  the  necessary  practical  experience,  even  though 
they  may  not  be  able  to  answer  questions  off-hand ;  and  those 
who  have  become  "  rattled  "  under  the  unusual  catechising, 
are  frequently  kindly  advised  by  the  examiner  to  "  come  and 
try  again. " 


\  838785  / 


INTRODUCTION. 


While  the  tendency  in  all  lines  of  engineering  is  toward 
thorough  familiarity  with  principles,  there  are  still  good 
chances  for  safe  men,  who  are  comparatively  unlearned,  to 
'  acquire  experience  by  actual  work  in  engine  rooms. 

The  relation  of  the  public,  to  the  issue  of  an  engineer's 
license,  is  the  same  as  that  in  which  it  stands  to  the  issue  of 
druggists  and  drug-clerk  licenses ;  that  is,  the  fundamental 
right  to  protect  itself  from  the  criminal  ignorance  of  un- 
worthy pretenders  in  handling  or  dispensing  dangerous  ma- 
terials. 

The  community  possesses  the  privilege  of  passing  upon 
the  qualifications  of  its  citizens  who  propose  to  manage 
and  control  machinery  or  chemicals  which,  used  without 
experience  or  good  natural  judgment,  are  liable  to  cause 
suffering  and  loss  to  innocent  persons. 

No  one  now  disputes  this  fundamental  principle  of  common 
law ;  and  it  is  a  notable  fact  that  the  more  competent  a  man 
is  for  the  performance  of  an  engineer's  duties,  the  more  he 
desires  an  honest  administration  of  the  laws  regarding  the 
subject,  and  a  safe  standard  of  qualification. 

Relating  to  the  office  of  an  Examining  Engineer  it  may  be 
said  that  the  position  is  no  sinecure,  for  he  should  be 
thoroughly  qualified  to  examine  and  pass  on  candidates,  so 
that  none  but  sober,  competent  and  careful  men  are  passed. 

As  examinations  must,  perforce,  be  conducted  by  practical 
engineers,  it  follows  that  upon  engineers,  as  a  class  and  pro- 
fession, depend  their  own  standing  in  the  community.  If 
the  Examiner  is  a  high-toned,  sober,  intelligent  man,  in  the 
course  of  time  the  men  he  passes  upon,  and  to  whom  he 
awards  licenses,  will  be  very  nearly  up  to  his  own  standard  as 


INTRODUCTION.  (x 


a  man.     It  would  be  worthy  of  interest  to  know  the  history, 
education  and  experience  of,  say,  one  hundred  of  the  exam- 
ining engineers  of  the  country  ;  for  these  men,  as  models,  the 
thousands  of  men  who  come  under  their  contact,  will  cer- 
tainly   emulate    and    approach  while  never  passing  their 
standard  of  excellence  ;  hence  the  future  welfare  of  steam 
engineering  as  a  profession  and  the  money  income  of  its 
members  depend  almost  wholly  upon  the  Examiners. 

The  test  to  which  Examiners  themselves  are  put  before 
receiving  their  appointments  is  very  severe,  and  to  have  held 
this  appointment  is  a  life-long  honor. 

In  a  recent  single  year's  report  of  the  New  York  City 
Steam  Boiler  Inspection  and  Engineer  Bureau,  there  were 
one  thousand  one  hundred  and  sixteen  examinations  of  new 
applicants  for  engineer's  licenses,  of  which  no  less  than  five 
hundred  and  thirty  were  found  incompetent  and  certificates 
refused. 

Of  the  five  hundred  and  eighty-six  successful  applicants, 
there  passed: 

On  the  first  examination  ...............     434 

On  the  second  examination  .....  „.....,,     126 

On  the  third  examination  ..............       23 

On  the  fourth  examination  .............        3 

-      686 

In  the  same  year  there  were  : 

Certificates,  renewed.  .................  4,697 

"          transferred.  ..............  1,883 

New  certificates  granted  ..............  686 

Making  the  total  number  in  force  .  .  6,566 


\ 


INTRODUCTION. 


These  six  thousand  five  hundred  and  sixty-six  certificates 
were  divided  thus : 

Certificates  of  the  1st  class 1,838 

1    "  «        2d  class 1,498 

"       3d  class 3,409 

Fire  department  engineers , 196 

Permits  for  boilers  only , 135 

6,566 

And  in  the  same  year  there  were  eight  thousand  four 
hundred  and  thirty  eight  inspections  made  of  steam  boilers. 

The  sum  of  two  dollars  for  each  certificate,  amounting  to 
$13,724.00  was  collected  and  paid  to  the  Treasurer  of  the 
Police  Pension  Fund  in  accordance  with  the  provisions  of 
Chap.  437,  Laws  of  1885. 

In  New  York  City  each  boiler  is  numbered  in  the  Records 
at  Headquarters ;  each  Engineer's  certificate  is  likewise  num- 
bered, and  a  heavy  fine  is  imposed  for  misusing  the  papers 
for  another's  benefit ;  and  in  case  of  the  loss  even  of  the 
papers  the  fact  must  be  immediately  reported  at  the  office  of 
the  Examiner,  and  a  fine  may  be  imposed  for  the  carelessness 
which  resulted  in  the  loss  of  the  certificate. 

It  will  thus  appear  that  each  license  applies  to  a  special 
steam-plant,  of  which  a  full  description  is  kept  in  the  files. 
When  an  engineer  changes  his  position  he  must  have  his 
certificate  "transferred."  By  this  it  will  be  seen  that  an 
applicant  must  first  secure  his  position ;  and  then  his  license 
— if  he  is  found  worthy — is  usually  granted  upon  the  written 
request  of  the  owner  of  the  steam-plant,  who  has  previously 
engaged  him,  and  fixed  the  details  of  service  and  compensa- 
tion. 


/  \ 


INTRODUCTION. 


The  certificates  are  for  one  year,  and  on  each  are  printed 
the  following  rules  : 

"  Holders  of  certificates  must  apply  to  the  officer  in  com- 
mand of  the  Sanitary  Company  for  re-examination  and  re- 
newal of  certificates  on  the  dates  of  the  expiration  of  the 
certificate.  This  date  of  expiration  will  be  found  printed  on 
the  face  of  the  certificate. 

The  certificate  allows  the  person  named  to  take  charge  of 
and  operate  the  steam-boiler  mentioned,  but  no  other,  and 
will  be  revoked  on  proof  of  negligence  or  insobriety." 


LAWS   OF   NEW   YORK. 

CHAPTER  635i, 

The  People  of  the  State  of  New  York,  represented  in  Senate 
and  Assembly,  do  enact  as  follows : 

Section  1.  Section  three  hundred  and  twelve  of  chapter 
four  hundred  and  ten  of  the  laws  of  eighteen  hundred  and 
eighty -two  is  hereby  amended  so  as  to  read  as  follows  : 

§  312.  The  board  of  police  shall  preserve  in  proper  form  a 
correct  record  of  all  inspections  of  steam  boilers  made  under 
its  direction,  and  of  the  amount  of  steam  or  pressure  allowed 
in  each  case,  and  in  cases  where  any  steam  boiler  or  the 
apparatus  or  appliances  connected  therewith  shall  be  deemed 
by  the  board,  after  inspection,  to  be  insecure  or  dangerous, 
the  board  shall  prescribe  such  changes  and  alterations  as 
may  render  such  boilers,  apparatus  and  appliances  secure 
and  devoid  of  danger.  And  in  the  meantime,  and  until  such 
changes  and  alterations  are  made,  and  such  appliances  at- 
tached, such  boiler,  apparatus,  and  appliances  may  be  taken 

NOTE.— Became  a  law  May  22, 1897,  with  the  approval  of  the  Gov- 
ernor. Passed,  three-fifths  being  present.  Accepted  by  the  city. 


xii  INTRODUCTION. 


under  the  control  of  the  board  of  police,  and  all  persons  pre- 
vented from  using  the  same,  and  in  cases  deemed  necessary, 
the  appliances,  apparatus,  or  attachments  for  the  limitation 
of  pressure  may  be  taken  under  the  control  of  the  said  board 
of  police.  And  no*owner,  or  agent  of  such  owner,  or  lessee 
of  any  steam  boiler  to  generate  steam,  shall  employ  any  per 
son  as  engineer  or  to  operate  such  boiler  unless  such  person 
shall  first  obtain  a  certificate  as  to  qualification  therefor 
from  a  board  of  practical  engineers  detailed  as  such  by  the 
police  department,  such  certificate  to  be  countersigned  by 
the  officer  in  command  of  the  sanitary  company  of  the 
police  department  of  the  city  of  New  York.  In  order  to  be 
qualified  to  be  examined  for  and  to  receive  such  certificate 
of  qualification  as  an  engineer,  a  person  must  comply,  to  the 
satisfaction  of  said  board,  with  the  following  requirements  : 

1.  He  must  be  a  citizen  of  the  United  States  and  over 
twenty-one  years  of  age. 

2.  He  must,  on  his  first  application  for  examination,  fill 
out,  in  his  own  handwriting,  a  blank  application  to  be  pre- 
pared and  supplied  by  the  said  board  of  examiners,  and 
which  shall  contain  the  name,  age,  and  place  of  residence  of 
the  applicant,  the  place  or  places  where  employed  and  the 
nature  ot  his  employment  for  five  years  prior  to  the  date  of 
his  application,  and  a  statement  that  he  is  a  citizen  of  the 
United  States.    The  application  shall  be  verified  by  him,  and 
shall,  after  the  verification,  contain  a  certificate  signed  by 
three  engineers,  employed  in  New  York  city,  and  registered 
on  the  books  of  said  board  of  examiners  as  engineers  work- 
ing at  their  trade,  certifying  that  the  statements  contained 
in  such  application  are  true.     Such  application  shall  be  filed 
with  said  board.         • 

3.  The  following  persons,  who  have  first  complied  with 
the  provisions  of  subdivisions  one  and  two  of  this  section, 
and  no  other  persons,  may  make  application  to  be  examined 
for  a  license  to  act  aa  engineer. 


INTRODUCTION.  xiii 


a.  Any  person  who  has  been  employed  as  a  fireman,  as  an 
oiler,  or  as  a  general  assistant  under  the  instructions  of  a 
licensed  engineer  in  any  building  or  buildings  in  the  city  of 
New  York,  for  a  period  of  not  less  than  five  years. 

b.  Any  persefh  who  has  served  as  a  fireman,  oiler  or  gen- 
eral assistant  to  the  engineer  on  any  steamship,  steamboat, 
or  any  locomotive  engineer  for  the  period  of  five  years  and 
shall  have  been  employed  for  two  years  under  a  licensed 
engineer  in  a  building  in  the  city  of  New  York. 

c.  Any  person  who  has  learned  the  trade  of  machinist,  or 
boilermaker  or  steamfitter  and  worked  at  such  trade  for 
three  years  exclusive  of  time  served  as  apprentice,  or  while 
learning  such  trade,  and  also  any  person  who  has  graduated 
as  a  mechanical  engineer  from  a  duly  established  school  of 
technology,  after  such  person  has  had  two  years'  experience 
in  the  engineering  department  in  any  building  or  buildings 
in  charge  of  a  licensed  engineer,  in  the  city  of  New  York. 

d.  Any  person  who  holds  a  certificate  as  engineer  issued 
to  him  by  any  duly  qualified  board  of  examining  engineers 
existing  pursuant  to  law  in  any  state  or  territory  of  the 
United  States  and  who  shall  file  with  his  application  a  copy 
of  such  certificate  and  an  affidavit  that  he  is  the  identical 
person  to  whom  said  certificate  was  issued.     If  the  board  of 
examiners  of  engineers  shall  determine  that  the  applicant 
has  complied  with  the  requirements  of  this  section  he  shall 
be  examined  as  to  his  qualifications  to  take  charge  of  and 
operate  steam  boilers  and  steam  engines  in  the  city  of  New 
York,  and  if  found  qualified  said  board  shall  issue  to  him  a 
certificate  of  the  third  class.     After  the  applicant  has  worked 
for  a  period  of  two  years  under  his  certificate  of  the  third 
class,  he  may  be  again  examined  by  said  board  for  a  certifi- 
cate of  the  second  class,  and  if  found  worthy  the  said  board 
may  issue  to  him  such  certificate  of  the  second  class  and 
after  he  has  worked  for  a  period  of  one  year  under  said  cer- 
tificate of  the  second  class  he  may  be  examined  for  a  certificate 


/  \ 


INTRODUCTION. 


of  the  first  class,  and  when  it  shall  be  made  to  appear  to  the 
satisfaction  of  said  board  of  examiners  that  the  applicant  for 
either  of  said  grades  lacks  mechanical  skill,  is  a  person  of 
bad  habits  or  is  addicted  to  the  use  of  intoxicating  beverages 
he  shall  not  be  entitled  to  receive  such  grade  of  license  and 
shall  not  be  re-examined  for  the  same  until  after  the  expira- 
tion of  one  year.  Every  owner  or  lessee,  or  the  agent  of 
the  owner  or  lessee,  of  any  steam  boiler,  steam  generator,  or 
steam  engine  aforesaid,  and  every  person  acting  for  such 
owner  or  agent  is  hereby  forbidden  to  delegate  or  transfer  to 
any  person  or  persons  other  than  the  licensed  engineer  the 
responsibility  and  liability  of  keeping  and  maintaining  in 
good  order  and  condition  any  such  steam  boiler,  steam  gen 
erator  or  steam  engine,  nor  shall  any  such  owner,  lessee  or 
agent  enter  into  a  contract  for  the  operation  or  management 
of  a  steam  boiler,  steam  generator  or  steam  engine,  whereby 
said  owner,  lessee  or  agent  shall  be  relieved  of  the  responsi- 
bility or  liability  for  injury  which  may  be  caused  to  person 
or  property  by  such  steam  boiler,  steam  generator  or  steam 
engine.  Every  engineer  holding  a  certificate  of  qualification 
from  said  board  of  examiners  shall  be  responsible  to  the 
owner,  lessee  or  agent  employing  him  for  the  good  care, 
repair,  good  order  and  management  of  the  steam  boiler, 
steam  generator  or  steam  engine  in  charge  of  or  run  or 
operated  by  such  engineer. 

§2.  This  act  shall  take  effect  immediately. 


KIDS 

TO 

ENGINEERS'   EXAMINATIONS. 


The  necessary  qualifications  to  secure  a  license  are  nearly 

in  the  following  order :  • 

p 
1st. — Character  or  general  fitness  for  the  trust. 

2d. — Knowledge  and  experience  relating  to  the  steam 
generator. 

3d. — Skill  in  the  running  of  the  steam-engine  and  other 
machines. 

Before  the  issue  or  the  refusal  of  a  license  to  an  applicant 
he  is  examined  personally,  and  alone,  by  one  of  the  Board, 
all  of  whom  are  practical  engineers ;  and  there  is  no  stated 
list  of  questions  either  oral  or  written. 

If  a  candidate  shows  by  his  answers  that  he  is  familiar, 
through  actual  experience  with  his  duties,  and  not  coached 
by  some  one  for  the  mere  purpose  of  obtaining  a  license,  ho 
is  entitled  to  his  papers. 

Relating  to  character  qualification,  it  may  be  said  that 
as  the  engineer  is  to  be  in  charge  with  an  almost  independ- 


14  ENGINEERS'   EXAMINATIONS. 

ent  trust  of  property  and  life,  the  Examiner  will,  before  any- 
thing else,  seek  to  ascertain  something  of  the  habits  and 
moral  principles  of  the  applicant.  No  man,  if  it  is  known, 
who  ever  yields  to  intoxication,  and  no  one  who  is  a  con- 
victed embezzler,  will  be  granted  a  license ;  without  question 
the  indefinable  marks  of  an  honest  man  go  very  far  towards 
securing  to  him  his  papers. 

The  reliable  engineer  is  nearly  always  a  man  of  thoughtful 
dignity  of  manners,  as  naturally  becomes  habitual  to  one  under 
an  unceasing  weight  of  responsibility,  involving  so  much  ; 
this  outward  evidence  of  inward  qualities  is  rightly  most 
favorable  to  an  applicant. 

Character  is  what  a  man  really  is,  and  a  good  character 
implies  many  virtues,  such  as  truthfulness,  courage  and  cool- 
ness under  sudden  danger,  a  habit  of  tidiness  in  person  and 
dress,  strict  honesty  and  large-mindedness ;  all  these  are  to 
be  expected  from  an  applicant  for  an  engineer's  papers. 

So  important  is  this  qualification— of  good  character — con- 
sidered, that  there  are  printed  on  each  of  the  seven  thousand 
licenses  issued  by  New  York  City  the  following  : 

Chapter  643,  Laws  of  1886.  "When,  on  examination  of 
an  applicant,  it  appears  to  the  satisfaction  of  the  Engineers 
that  he  lacks  natural  capacity,  or  mechanical  skill,  knowl- 
edge or  experience ;  or  is  unfitted  by  habits  of  insobriety  to 
perform  the  required  duties  in  a  manner  consistent  with 
safety  of  life,  a  certificate  of  qualification  will  be  denied. 
Renewals  of  certificates  will  be  refused,  and  certificates  will 
be  revoked  on  proof  of  like  deficiencies." 

For  many  reasons  a  good  character  is  the  first  requisite  for 
the  granting  of  a  license,  coming  even  before  skill  and 


ENGINEERS'    EXAMINATIONS.  15 

knowledge  of  the  business  It  is  on  account  of  its  relative 
importance  that  applicants  are  first  required  to  give  an  ac- 
count of  their  experience  in  the  practical  duties  of  engineer, 
machinist  or  fireman. 

As  to  the  general  fitness  of  the  applicant,  it  may  be  said 
that  age  implying  a  certain  length  of  experience  is  necessary ; 
while  on  the  other,  extreme  age.  even  with  great  skillful- 
ness,  if  accompanied  by  bodily  weakness,  is  a  bar  to  passing. 
Defective  eyesight,  an  evidence  of  extreme  nervousness,  and 
certain  bodily  defects,  are  very  potent  reasons  for  withhold- 
ing consent. 

Secondly,  the  examiner  will  proceed  to  ascertain  the 
applicant's  knowledge  of  the  steam  generator.  No  applicant 
wanting  in  practical  experience  in  the^care  and  management 
of  the  steam  boiler  will  be  permitted  to  pass.  If  there  were  no 
liability  of  steam  explosions  there  would  be  no  need  of  issuing 
licenses  in  stationary  engineering  service  any  more  than 
for  a  license  to  run  wood  or  iron  working  machinery,  pile 
drivers,  or  the  thousand  and  one  machines  used  in  modern 
industry ;  for  example,  no  license  is  required  to  run  a  water- 
mill,  however  large,  unless  it  has  a  steam  boiler  on  the 
premises. 

Accidents  in  steam  plants,  like  the  bursting  of  fly-wheels 
and  breaking  of  cylinder-heads,  even  if  accompanied  by  in- 
jury and  loss  of  life,  cause  no  uneasiness  in  the  public  mind, 
and  carry  no  personal  discredit  to  the  Examiner ;  but  if  a 
license  is  granted  to  an  unworthy  person,  and  an  explosion 
of  a  steam  boiler  occurs,  causing  personal  injury  or  loss  of 
life,  then  the  public,  through  its  Coroner's  or  other  juries, will 


16  ENGINEERS1    EXAMINATIONS. 

blame  the  Examiner  for  being  remiss  in  guarding  its  safety, 
as  well  as  the  person  in  direct  charge.  Hence,  the  sharpest 
questionings  come  in  reference  to  the  steam  boiler. 

While  the  first  element  of  stress  is  laid  upon  character, 
the  second  is  properly  put  upon  the  knowledge  of  the  steam 
generator,  and  the  greater  portion  of  this  book  of  "aids" 
will  be  devoted  to  the  problems  relating  to  its  construction, 
safety  and  management. 

Third  will  come  all  these  questions  relating  to  the  steam-en- 
gine, pumps,  piping  and  general  knowledge,  which  go  to  prove 
that  the  applicant  is  really  an  engineer  (that  is,  an  ingenious 
person),  capable  of  the  position  of  trust  to  which  he  aspires. 

So  very  different  in  responsibility  are  the  positions  required 
to  be  filled  by  the  engineer  that  it  is  almost  always  a  matter 
of  individual  judgment  with  the  examiner  as  to  the  fitness 
of  the  man  for  the  place  ;  and  in  forming  this  judgment 
and  deciding  aright  both  the  discernment  and  skill  of  the 
examining  engineer  are  exhibited. 

In  the  latter  part  of  this  work  will  be  found  several  ex- 
tracts from  city  and  United  States  laws,  relating  to  engineer's 
licenses  and  examinations.  These  will,  doubtless,  form 
models  for  other  parts  of  the  country,  as  yet  without  laws 
bearing  on  the  subject,  as  they,  one  by  one,  adopt  the  system 
of  protection  found  so  useful,  where  it  has  been  tested. 


CLASSIFICATION   OF   KNOWLEDGE.  17 


CLASSIFICATION  OF  KNOWLEDGE  THE  KEY 
TO  SUCCESS. 


"  When  a  man's  knowledge  is  not  in  order,  the  more  he  has  of  it  the 
worse  he  is  oJV'— OLD  PROVERB. 

This  old  saying  conveys  the  strange  truth  that  sometimes 
the  more  a  man  knows,  the  more  useless  is  what  he  knows. 
It  is  true,  notwithstanding  its  strangeness,  and  it  is  true 
especially  in  practical  steam  engineering. 

On  a  certain  corner  in  the  Bowery  of  New  York  City  may 
be  seen  a  store  window  packed  full  of  all  kinds  of  cutlery — 
razors,  corkscrews,  butcher  knives,  files,  screw  drivers, 
pistols,  hammers,  boxes  of  drawing  tools  and  a  hundred 
other  things  in  the  hardware  line.  These  are  all  in  one  jum- 
bled mass  in  indescribable  confusion,  and  are  an  emblem  of 
the  disorder  in  the  mind  of  an  unapt,  blundering,  unskillful 
man  in  the  engine  or  boiler  room.  He  has  the  knowledge, 
perhaps,  but  it  is  never  available  when  needed. 

Now,  on  Park  Row,  a  little  south,  there  is  a  regular  hard- 
ware store  with*a  stock  of  goods  a  hundred  times  the  variety 
land  a  thousand  times  as  large  as  that  in  the  Bowery,  and  yet 
scores  of  men  and  many  teams  serve  hundreds  of  customers 
every  day,  and  block  the  sidewalks  with  the  incoming  and 
outgoing  loads  of  their  ware,  handled  in  the  big  many 


18  CLASSIFICATION  OF  KNOWLEDGE. 

storied  building  and  all  without  confusion,  loss  or  hurry. 
This  is  also  a  symbol  of  another  kind  of  man  who  has  his 
wide  and  extensive  knowledge  well  in  hand  for  ready  use, 
who  easily  may  assume  with  credit  the  position  of  chief 
engineer. 

What  is  the  key  to  success  in  the  management  of  a  steam 
plant  and  of  personal  advancement?  It  consists  in  the 
scientific  or  orderly  arrangement  of  the  various  knowledge 
required  to  make  the  experienced  engineer. 

Not  only  tne  chief  but  the  assistant  engineer,  the  oiler  and 
the  fireman  should  strive  towards  this  due  classification — as 
soon  as  a  fact  is  acquired  let  it  be  stored  away  in  its  proper 
place  in  the  mind.  Facts  about  steam  with  the  steam 
(mental)  department — facts  about  the  engine  in  the  engine 
(mental)  department ;  facts  about  piping  and  valves  with  the 
pipe  and  va!T'e  (mental)  department,  etc.,  etc. 

In  this  way  the  mind  and  memory  are  filled  with  available 
knov.dedge  like  a  well  written  book  with  a  reference  index. 

For  instance  all  the  various  items  of  information  relating 
to  the  physical  properties  of  steam  should  be  grouped  together 
in  the  engineer's  mind,  or  he  should  know  where  and  when 
to  lay  his  hands  upon  needed  information  relating  to  this 
subject.  Example:  There  is  a  table  of  steam  properties 
called  Regnault's  Tables,  which  show  the  lemperature  of 
steam  at  the  different  pressures,  the  volume  per  pound  in 
cubic  feet  at  the  different  temperatures,  etc.  Now  it  is  not 
necessary  to  carry  all  the  figures  in  one's  mind,  it  is  only 
necessary  to  know  of  the  existence  of  the  Tables,  where  they 


CltASSIFICATION'  OF  KNOWLEDGE.  19 

t 

are  to  be  found — in  what  book  and  in  what  library,  and  finally 
to  accurately  apply  the  figures  to  the  problem  to  be  decided. 

To  know  these  and  other  fundamental  laws  is  a  long  step 
in  the  science  of  steam  engineering  and  the  remuneration  is 
large  to  the  man  who  knows  and  can  use  his  knowledge. 

The  rudiments  of  steam  engineering  can  be  acquired  by 
about  two  years  of  constant  application,  and  close  observation, 
by  a  person  who  has  a  liking  for  the  work.  A  person  who 
does  not  like  to  perform  the  duties  required  will  never  acquire 
"full  competency"  for  the  duties  required  of  a  chief  engi 
neer,  for  the  reason  that  he  will  not  have  the  opportunity. 

A  system  of  education  that  tends  to  broaden  the  mind  and 
thus  render  it  capable  of  dealing  confidently  with  large 
questions  is  not  only  most  likely  to  make  the  engineer  edu- 
cated under  it  more  respected  by  those  with  whom  he  comes 
into  contact  in  professional  life,  but  it  gives  him  a  wider 
range  of  opportunities. 

The  immense  magnitude  of  modern  steam  plants  and  their 
combination  of  Steam,  Electricity,  Refrigeration,  Transpor- 
tation, etc. ,  calls  for  first  class  men  to  manage  the  complex 
machinery. 

This  theme  is  a  difficult  although  necessary  one,  and 
advice  relating  to  it  may  be  summed  up  thus — 

FIRST.     Do  not  "lumber  "  the  mind  with  useless  matters. 

SECOND.     Be  sure  of  the  truth  of  each  single  fact. 

THIRD.  Store  the  fact  or  item  of  information  away  in  the 
mind  with  other  kindred  items  relating  to  the  same  depart- 
ment of  engineering. 


CLASSIFICATION  OF  KNOWLEDGE. 


To  make  tne  most  of  oneself  is  a  problem  which  has  been 
answered  by  the  word  concentration.  Keep  close  to  one  line 
of  advancement  and  be  content  to  be  ignorant  of  some  things 
in  order  to  know  thoroughly  some  others,  The  path  being 
chosen,  ther?  let  the  advance  be  persistent  and  unceasing.  It 
was  thus  that  Stephenson  produced  such  results  in  locomo- 
tion, and  Watt  such  wonders  with  the  steam  engine. 

This  persistent  industry  is  not  irksome.  It  carries  its  own 
reward,  and  the  results  are  definite  and  sure. 

"  One  step  and  then  another, 

And  the  longest  walk  is  ended ; 
One  stitch  and  then  another, 

And  the  largest  rent  is  mended. 
One  brick  upon  another, 

And  the  highest  wall  is  made : 
One  flake  upon  another, 

And  the  deepest  snow  is  laid. 


STEAM  BOlLEtt. 


THE   STEAM   BOILER. 


While  the  shapes  and  forms  in  which  steam  generators 
have  been  constructed  are  many,  they  all  agree  in  one  point 
—they  are  closed  vessels  strongly  made  so  as  to  withstand  an 
internal  pressure  of  considerable  force. 

In  engineering  terms  this  force  is  called  the  steam  press- 
ure and  it  varies  from  5  to  300  Ibs.  per  square  inch.  It  is  the 
first  rule  in  the  design  of  steam  boilers  to  provide  against 
this  varying  internal  force. 

While  the  sphere  is  the  strongest  form  of  vessel  to  resist 
internal  pressure,  there  are  many  practical  reasons  which 
prevent  its  being  used  for  the  purpose.  Next  to  the  sphere 
the  cylindrical  form  is  the  simplest  and  strongest,  and  is  now 
universally  adopted. 

The  steam  boiler  has  two  essential  parts,  the  furnace 
which  contains  the  fuel  to  be  burnt  and  the  boiler  containing 
the  water  to  be  evaporated.  Within  the  boiler  there  must  be 
steain-room  as  well  as  water  space — outside  there  must  be 
heating  surface  and  a  chimney  or  other  apparatus  to  convey 
away  the  waste  products  of  combustion. 


ENQINE1DRS' 


Questions  and  Answers  Relating  to  Materials 
for  Boilers. 

Ques.  What  is  the  meaning  of  Tensile  strength  when  ap- 
plied to  rivets,  braces  and  boiler  plates  ? 

Ans.  It  is  that  amount  of  force — usually  ex- 
pressed in  pounds — which,  steadily  and  slowly  ap- 
plied in  a  straight  line,  just  overcomes  the  cohesion 
of  the  particles  and  pulls  it  into  separate  parts 

Ques.     What  is  the  meaning  of  shearing  strength  ? 

Ans.  It  is  that  amount  of  force — usually  ex- 
pressed in  pounds — which,  if  steadily  and  slowly 
applied  to  the  rivet,  at  right  angles  to  its  axis,  causes 
it  to  separate  in  parts,  which  slide  over  each  other. 
This  separation  is  nearly  always  at  right  angles,  and 
in  common  language  is  called  "  shearing  off  the 
the  rivets." 

Ques.    What  is  the  meaning  of  elastic  limit  ? 

Ans.  This  is  the  point  to  which  steel  or  iron  can 
be  stretched  out,  and  from  which  the  metal  will 
return  to  its  original  position.  When  steel  is  pulled 
beyond  its  limit  of  elasticity,  it  does  not  return  to 
its  old  place  ;  the  "bagging"  of  a  burnt  sheet  over 
the  fire  is  an  example  of  the  plate  having  been 
Stretched  beyond  its  limit  of  return. 


QUESTIONS   AND   ANSWERS. 


(Jues.    What  is  the  meaning  of  ductile  ? 

Ans.  The  material  is  "  ductile/'  when  it  can  be 
extended  by  a  pulling  or  tensile  force  and  remain 
extended  after  the  force  is  removed  ;  the  greater 
the  permanent  extension  the  more  ductile  the  ma- 
terial. 

(Jues  What  is  the  meaning  of  ••  tough  "  when  applied  to 
iron  or  steel  ?  » 

Ans.  The  material  is  said  to  be  tough  when  it 
can  be  bent  first  in  one  direction  and  then  the  op- 
posite direction  without  breaking  or  cracking.  The 
greater  the  angles  it  bends  through  (coupled  with  the 
number  of  times  it  bends)  the  tougher  it  is. 

Qnes.    What  is  the  meaning  of  malleable  ? 

Ans,  This  is  the  term  applied  to  iron  or  steel 
when  it  can  be  extended  by  hammering  or  rolling 
without  cracking  and  remain  extended  ;  the  more  it 
can  be  extended  without  fracturing,  the  more  malle- 
able it  is. 

Ques.    What  is  weldable  iron  or  steel  ? 

Ans.  This  is  the  term  which  is  applied  to  the 
material  if  it  can  be  united  when  hot  by  hammering 
or  pressing  together  the  heated  parts.  The  nearer 
the  properties  of  the  metal  after  being  welded  are 
to  what  they  were  before  being  heated  and  welded, 
the  more  weldable  it  is. 

(Jues.  What  does  homogeneous  mean  when  applied  to 
boiler  plates  ? 


ENGINEERS  EXAMINATIONS. 


Ans.  This  word  describes  material  of  the  same 
structure  and  nature ;  where  the  grain  or  fibre  of 
the  plate  is  the  same  in  every  direction. 

Ques.    What  is  the  meaning  of  cold-short  iron  or  steel  * 

Ans.  This  is  a  name  given  to  the  material  when 
it  cannot  be  rolkd  or  hammered,  or  be  bent  when 
cold  without  cracking;  such  a  material  can  be  worked 
or  bent  when  at  a  great  heat,  but  not  at  any  tem- 
perature greater  than  that  assigned  to  dull-red. 

Ques.    What  is  the  meaning  of  "  hot-short  V" 

Ans.  This  is  when  the  material  cannot  be  easily 
worked  under  the  hammer,  or  by  rolling  at  a  red- 
heat,  at  any  temperature  which  is  assigned  to  a  red 
heat,  without  fracturing  or  cracking,  such  a  material 
may  be  worked  or  bent  at  a  less  heat. 

Ques.    What  is  the  meaning  of  elongation  of  metals  ? 

Ans.  The  amount  of  stretching  usually  expressed 
in  Ibs.  which  a  test  piece  will  bear,  due  to  a  steady 
and  slowly  applied  force  before  it  is  pulled  into 
parts. 

Ques.  Describe  tht  qualities  which  should  be  possessed  by 
a  good  boiler-plate  ? 

Ans.  The  plate  should  not  be  too  large,  and 
should  have  been  satisfactorily  tested  at  the  mil] 
by  suitable  bending  tests,  and  by  the  testing  ma- 
chine, each  sheet  being  marked  with  the  maker's 
name,  with  the  figures  showing  what  tensile 
Strength  it  had  stood  in  the  test. 


QUESTIONS   AND   ANSWERS. 


Ques.  Eepeat  the  answer,  using  the  definitions  for  boiler 
materials  in  their  proper  places  ? 

Ans.  The  material  should  be  homogeneous,  and  of 
suitable  tensile  strength  and  elongation,  best  suited  for 
the  purpose,  having  an  elastic  limit  that  will  ensure 
the  boiler  being  reliable  ;  it  should  be  tough  and 
ductile  ;  the  material  should  be  malleable,  and  in  some 
cases  weldable  j  that  which  is  of  a  decidedly  cold- 
short or  hot-short  nature  should  be  avoided. 

Ques.    What  is  steel  ? 

Ans.  Steel  is  iron  with  a  mixture  of  carbon  or 
an  alloy  of  iron — the  alloy  being  principally  carbon 
steel  ;  can  be  melted  like  cast  iron  and  welded  like 
wrought  iron.  There  are  hard  and  soft  steels, 
according  to  the  process  of  production  and  propor- 
tion of  alloy. 

Ques.    What  is  iron? 

Ans.  It  is  one  of  the  original  substances  of  which 
the  globe  is  composed.  There  is  very  little  pure 
iron,  it  being  nearly  always  found  combined  with 
other  things.  Wrought  iron  is  iron  with  the  impur- 
ities worked  (or  wrought  out)  and  thus  rendered 
soft  and  malleable,  ready  to  be  beaten  by  the  ham- 
mer into  any  desired  form  or  rolled  into  thin  plate.* 

Ques.    What  is  the  tensile  strength  of  steel  and  iron  ? 

Ans  Of  iron  according  to  the  table,  50,000  to 
the  square  inch  average — of  steel  about  70,000  Ibs 


*  NOTE.  A  bar  of  Iron  worth  $5.00,  it  Is  stated,  is  worth  $10.50  when  made  ln*0 
horse-shoes,  $55.00  in  the  form  of  needles,  $3,285  in  penknife  blades,  $29,480  at 
shirt  buttons,  and  $250,000  in  balance  suruiua  of  watches. 


26  ENGINEERS'  EXAMINA'flQNS. 

Ques.    What  is  the  difference  between  steel  and  iron  ? 

Ans.  The  steel  in  ordinary  use  is  an  alloy  of  iron 
which  is  cast  while  in  a  fluid  state  into  a  malleable 
ingot.  To  be  steel  it  must  be  malleable  and  the 
product  of  melting  or  fusion.  This  definition 
excludes  pig-iron  which  is  fused  or  melted,  but  not 
malleable;  and  wrought  iron  which  is  malleable  but 
not  fused  or  melted. 

Ques.     What  is  an  alloy,  define  it  ? 

Ans.  An  alloy  is  a  mixture  or  compound  of  two 
or  more  metals.  Ex.:  two  parts  of  tin  and  six  parts 
of  lead  is  "an  alloy  "  suitable  for  fusible  plugs  and 
which  melts  at  380°  fahrenheit.  To  alloy  is  usually 
to  reduce  the  quality  of  one  of  the  parts,  and  the 
least  valuable  is  sometimes  called  "  an  alloy." 


Questions   and  Answers   Relating  to  the  Ex- 
pansion and  Contraction  of  Steam  Boilers* 

Ques.  When  a  boiler  is  in  use  what  is  the  effect  of  heating 
and  cooling  it  ? 

Ans.  The  heat  expands  and  enlarges  the  whole 
structure,  and  it  should  be  so  constructed  and  set  in 
the  brick  work,  that  this  change  in  form  may  be  as 
uniform  as  possible — one  part  equally  with  another. 

Ques.    Does  the  cold  contract  the  boiler  ? 

Ans.  Yes,  and  the  process  of  enlarging  and  con- 
tracting is  a  continual  process,  as  long  as  the  boiler 
is  making  steam. 


QUESTIONS  AND  ANSWERS.  27 

Ques.  What  is  the  effect  of  unequal  expansion  and  con- 
traction ? 

Ans.  It  is  a  severe  test  of  the  strength  of  the 
boiler,  the  tubes  or  flues  expanding  lengthwise  with 
a  force  sufficient  to  tear  the  heads  out  of  the  boiler. 

The  smaller  the  proportion  of  the  surface  of  a 
boiler  that  is  exposed  to  the  heat,  the  more  active 
will  be  the  effect  of  the  expanding  and  contracting 
forces,  and  in  the  case  of  boilers,  set  more  than 
half  exposed  to  the  influence  of  the  atmosphere,  the 
power  exercised  by  the  expansive  heat  of  the  fire 
below  and  the  contraction  due  to  the  low  tempera- 
ture above,  are  almost  enough  to  tear  the  boiler  to 
pieces. 

Ques.    Is  any  more  to  be  said  upon  this  ? 

Ans.  It  is  the  unequal  expansion  of  the  shell  and 
tubes  that  really  does  more  injury  to  a  steam  boiler 
than  the  expansion  and  contraction  due  to  changes 
in  the  pressure  of  steam  ;  the  leakage  and  cases  of 
rupture  that  so  often  occur  in  the  lower  seams  and 
along  the  bottom  of  horizontally  fired  boilers  are 
unquestionably  due  to  these  causes;  in  very  many 
instances  forced  firing  in  getting  up  steam  on  first 
starting  the  boiler  is  to  blame. 

(Jues.  Is  the  force  of  expansion  and  contraction  known  so 
that  it  can  be  "nearly  "  calculated  ? 

Ans.  Yes,  iron  will  exert  a  strain  of  150  pounds 
per  square  inch  for  every  degree  of  temperature. 
Suppose  iron  has  been  heated  to  350  degrees  and 


ENGINEERS'  EXAMINATIONS. 


cooled  down  to  60  degrees  ;  if  it  is  securely  riveted 
or  otherwise  fastened  it  will  be  cooled  350°  —  6o°= 
290°  X  150  =44,500=22^  tons,  on  every  square 
inch  of  section. 

Qnes.  Name  an  instance  where  this  force  is  likely  to  be 
dangerously  exerted  ? 

Ans.  Where  the  tubes  are  placed  very  near  the 
bottom  of  a  boiler,  in  which  case  the  pressure  is  all 
on  the  lower  side  of  the  heads  and  the  plates  that 
keep  them  together  ;  it  is  not  unusual  for  these 
plates  to  be  ruptured  or  the  seams  sprung  under- 
neath, causing  troublesome  and  often  dangerous 
leaks. 

Ques.    How  are  these  difficulties  to  be  avoided  ? 

Ans.  To  avoid  the  injuries  so  often  caused  to 
boilers  in  this  manner,  it  is  necessary,  therefore,  to 
exercise  great  care  in  raising  steam  in  new  boilers 
or  those  that  have  been  blown  out  and  allowed  to 
cool  down.  The  fire  should  be  raised  moderately 
and  gradually,  and  the  boiler  moderately  filled  with 
water,  so  that  the  increase  in  the  temperature  may 
be  gradual.  In  cooling  off  a  boiler  the  same  care 
must  be  exercised  ;  nor  should  the  furnace  doors  be 
suddenly  thrown  open  or  any  other  proceeding 
taken  that  will  result  in  suddenly  lowering  the  boiler 
temperature,  a  rapid  decrease  in  the  heat  being  quite 
as  bad  for  the  safety  and  durability  'of  the  boiler  as 
the  immoderate  and  unequal  increase  above  referred 
to. 


ENGINEER'S  EXAMINATIONS.  29 


BOILER  BRACES  AND  STAYS. 


Portions  of  boiler  shells  which  are  flat,  or  which  otherwise 
deviate  from  the  round  or  egg  shape,  are  necessarily  strength- 
ened by  means  of  stays  or  braces,  against  the  enormous 
outward  pressure  caused  by  the  steam. 

The  ori ly  forms  for  the  shell  of  boilers  which  are  safe 
against  bursting  by  internal  pressure,  without  the  aid  of 
stays,  are  the  cylinder  and  the  sphere  or  egg  shape. 

The  tubes  which  extend  from  end  to  end  of  the  tubular 
boiler,  it  has  been  proved,  furnish  sufficient  holding  power  to 
amply  stay  the  part  of  the  head  to  which  they  are  attached 
and  also  two  inches  above  the  upper  row  of  tubes. 

The  flanges  of  the  head  being  securely  united  to  the  shell, 
and  being  also  curved  or  dished,  it  may  likewise  be  safely 
assumed  that  no  braces  need  be  provided  for  that  part  of  the 
head  which  lies  within  three  (3)  inches  of  the  shell. 

The  part  of  a  horizontal  tubular  boiler  which  needs  to  be 
braced  therefore  consists  of  a  segment  of  a  circle  "whose 
circumference  lies  three  inches  within  the  circle  of  the  shell 
and  whose  base  is  two  inches  above  the  upper  row  of  tubes. 

Thus  in  a  6-foot  boiler,  whose  upper  row  of  tubes  is  26 
below  the  top  of  the  shell,  the  part  of  the  head  which  requires 
bracing  consists  in  a  segment  of  a  circle,  the  diameter  of 


30  QUESTIONS  AND  ANSWERS. 

which  is  60  inches  and  the  heighth  of  which  is  21  inches;  21 
inches  being  the  measured  heighth,  26  inches  less  the  3 
inches  supported  by  the  flange  and  the  2  inches  supported  by 
the  flues. 

Each  square  inch  of  this  flat  surface  must  be  practically 
supported  by  the  braces,  owing  to  the  thinness  of  the  plates, 
of  which  the  boiler  heads  are  constructed  ;  and  large  allow- 
ance must  be  made  for  weakening  caused  by  the  age  and  use 
of  the  boiler. 


Questions    and    Answers    Relating   to    Boiler 
Braces  and   Stays. 

Ques.  What  are  some  of  the  names  of  boiler  braces  and 
stays  ? 

Ans.  Crowfoot-brace,  jaw-brace,  head-to-head- 
brace  or  through  braces,  gusset-stay. 

Ques.    What  are  through  braces  ? 

Ans.  The  same  as  head- to- head  braces,  /.  e.,  they 
pass  from  one  end  of  the  boiler  to  another. 

C^ues.    What  is  the  crowfoot  brace  ? 

Ans.  This  is  sometimes  called  the  "  solid  brace  " 
because  it  is  made  of  one  piece  of  iron  with  both 
ends  "  flanged  out  "  for  the  purpose  of  riveting  to 
both  the  shell  and  head. 

Ques.    What  are  radial  braces  ? 


ENGINEERS* 


31 


Ans.  These  include  the  crowfoot  and  braces 
attached  to  T  iron,  and  so  placed  as  to  run  back  to 
the  shell  in  a  direct  line  from  the  head  fastening,  at 
a  proper  angle. 


Ques.  What  is  the  difficult  problem  in  arranging  the 
braces  inside  a  steam  boiler  ? 

Ans.  It  is  of  allowing  access  to  the  boiler  for 
examination  and  still  to  properly  arrange  the  braces 
so  that  each  shall  bear  its  due  proportion  of  load 

(Jues.     Of  what  material  should  braces  be  made  ? 

Ans.  Of  the  best  iron,  without  weld,  and  should 
be,  where  threaded,  upset  for  six  or  eight  inches 
from  the  ends,  so  that  when  these  ends  are  threaded 
the  diameter  at  the  bottom  of  the  thread  shall 
slightly  exceed  the  diameter  of  the  brace.* 


*  With  radial  bracing  greater  strength  is  obtained  by  increasing 
the  number  of  the  braces.  With  through  braces,  on  the  other  hand, 
increased  pressure  is  provided  for  by  an  increase  in  the  size  of  the 
braces.  This  is  an  important  consideration ;  for  braces  that  at  100 
pounds  pressure  sustain  a  stress  of  7,500  pounds  per  square  inch,  would 
not  be  proper  if  the  boiler  were  to  carry  125  or  150  pounds.  The  braces 
should  always  be  proportioned  to  the  surface  they  have  to  sustain, 
and  to  the  pressure  of  the  steam.  It  may  seem  needless  to  refer  to  so 
obvious  a  fact  as  this,  but  our  experience  has  shown  that  too  little 
attention  is  sometimes  paid  to  it,  and  hence  we  feel  called  upon  to 
urge  its  importance.— The  Locomotive,  Feby.,  189k. 


82 


QUESTIONS  AND  ANSWERS. 


(Jucs.    What  stress  is  allowed  on  boiler  stays  ? 

Ans.  The  greatest  stress  to  which  a  boiler  stay 
should  be  exposed  is  6,000  Ibs.  per  square  inch  of 
section*  at  smallest  part  of  stay  if  made  of  iron  and 
but  little  more  if  made  of  unwelded  steel. 

Ques.  How  do  you  find  the  absolute  stress  or  strain  on  the 
flat  surface  of  a  steam  boiler,  which  is  carried  by  the  stays  ? 

Ans.  Choose 
three  stays  at  three 
corners  of  a 
square  —  multiply 
the  sides  in  inches 
and  the  result  is 
the  number  of 
square  inches  of 
surface  depend- 
ing upon  one  bolt 
or  stay  for  sup- 
porting strength. 

Ques.     Give  an  example. 

Ans.  Suppose  the  stays  measure  5  inches  from 
center  to  center  each  way  with  steam  at  60  Ibs., 
then  : 

5X5  =  25X60=  1,500  Ibs.  borne  by  i  stay.f 

*  This  is  the  U.  S.  Government  rule— iV  to  yV  the  tensile  strength, 
of  the  iron  or  steel  used  for  braces  is  a  safe  rule  to  follow.  Many 
State  and  City  Ordinances  allow  7,500  Ibs.  net  etress. 

t  The  cut  exhibits  more  clearly  the  process.  Measure  the  distance 
from  A  to  3  in  inches  and  from  A  to  C.  Multiply  by  steam  pressure. 


ENGINEERS    EXAMINATIONS.  J*3 

(Jues.  How  do  you  ascertain  the  number  and  size  of  the 
stay  bolts  to  be  used  on  a  flat  surface  in  a  boiler  ? 

Ans.  By  finding  the  total  pressure  on  the  unsup- 
ported portion  and  dividing  it  by  the  number  of 
stays,  each  of  which  should  be  strong  enough  to 
bear  its  proportion.* 

Ques.  In  examining  the  interior  of  the  boiler,  which  should 
be  done  periodically,  what  are  some  of  the  defects  for  which 
you  would  be  on  the  lookout  ? 

Ans.  For  slack  braces,  for  pins  missing  from  the 
braces,  and  also  to  see  that  none  of  the  braces  have 
more  than  their  due  share  of  strain,  and  for  leaky 
socket-bolts. 

(Jues.    What  else  would  you  particularly  look  for  ? 

Ans.  For  defective  riveting,  defective  heads  to 
the  rivets,  and  for  broken  and  loose  stays  and  braces. 

(Jues.  When  defects  are  found  who  is  the  best  party  to 
make  the  repairs  ? 

Ans.     An  experienced  boiler  maker. 

(Jues.  If  no  good  boiler  maker  was  available  what  would 
you  do  then  ? 

Ans.  I  would  run  no  risk  but  wait  until  one 
could  be  had — unless  I  myself  was  capable  of  mak- 
ing a  temporary  repair,  and  then  I  would  try  and 
prove  myself  an  engineer  worthy  of  my  position. 


*  The  stays  should  be  well  fitted  and  each  one  carefully  tightened 
and  as  far  as  possible  each,  stay  in  a  group  should  have  the  same  reg- 
ular  strain  upon  it. 


84  ENGINEERS' 


Ques.    When  a  new  boiler  is  put  into  service  and  it  begins 

to  exhibit  signs  of  distress  and  leakage  after  being  fired  up 
for  a  few  days  or  weeks,  what  is  usually  the  cause  ? 

Ans.     It  is  probably  the  effect  of  overstraining. 

Ques.    What  is  the  cause  of  this  ? 

Ans.  •  Frequently  the  end  plates  are  too  thick  or 
too  rigidly  stayed,  thus  preventing  the  plate  from 
slightly  yielding  or  "  breathing"  in  sympathy  with 
the  lengthening  and  shortening  of  the  flue  tubes, 
constantly  taking  place  with  each  variation  of  tem- 
perature. 

Qnes.    What  remedy  is  there  for  this  ? 

Ans.  That  is  a  boiler-  maker's  job,  and  it  is  some- 
times done  by  re-riveting  the  gussett  stays  which 
hold  the  ends  and  sides  of  the  boiler  together. 

Ques.    Name  other  things  causing  overstraining  ? 

Ans.  Overheating  the  plates,  resulting  from  the 
use  of  impure  water  —  this  is  a  very  frequent  cause 
of  the  failure  of  comparatively  new  boilers,  the 
deposits  cause  uneven  expansion  and  contraction. 
Again,  the  presence  of  oils  in  the  boiler,  admitted 
with  the  feed  water  when  taken  from  the  hot  well  of 
a  jet  condensing  engine,  or  admitted  with  the  steam 
from  the  cylinders.  This,  especially  where  the  water 
contains  carbonate  of  lime,  is  responsible  fora  great 
deal  of  the  trouble  arising  from  straining. 


QUESTIONS  AND  ANSWERS.  35 

Questions  and  Answers  Relating  to  Incrusta- 
tion and  Scale* 

When  steam  is  used  through  the  cylinder  or  heat- 
ing pipes,  all  of  the  impurities,  existing  in  nearly 
all  water,  remain  to  vex  the  engineer,  to  impede  the 
action  of  the  generator,  and  to  ultimately  even  des- 
troy it.  For  instance,  a  150  h.  p.  boiler  will  evapor- 
ate at  least  30,000  Ibs.  of  water  in  each  day  of  ten 
hours,  and  in  a  month,  say,  400  tons.  In  a  compara- 
tively pure  water  there  would  be  100  Ibs.  of  solid 
matter  in  that  quantity,  and  in  many  kinds  of  spring 
water  as  much  as  2,000  Ibs.,  and  all  this  remains 
after  the  steam  is  removed.  In  some  "  river  waters" 
such  has  been  the  condition  of  the  interior  of  the 
steamboat  boilers  that  it  has  resembled  "  mush  "  in 
consistency. 

The  impurities  are  simply  foreign  bodies,  which 
have  no  legitimate  place  in  the  boiler,  and  are  to 
be  expelled  as  dangerous  foes. 

The  sediment  remaining  after  the  extraction  of 
the  steam  forms  scale  ;  and  the  presence  of  scale  or 
sediment  in  a  boiler  results  in  loss  of  fuel,  burning 
and  cracking  of  the  boiler,  predisposes  to  explosion, 
and  leads  to  extensive  repairs.  It  is  estimated  that 
the  presence  of  1-16  inch  of  scale  causes  a  loss  of  13 
per  cent,  of  fuel,  %  inch  38  per  cent.,  and  ^  inch  60 
per  cent. 


36  ENGINEERS'  EXAMINATIONS. 

(Jues.  What  effect  does  the  accumulation  of  scale  on  the 
inteiior,  and  of  soot  on  the  exterior  of  a  boiler,  have  upon 
the  economy  of  the  boiler  ? 

Ans.  The  result  is  to  largely  increase  the  amount 
of  fuel  consumed,  frequently  as  much  as  one-fourth 
in  cases  of  bad  scaling. 

The  most  common  defects  produced  are  serious 
leakage  around  tube  ends,  incrustation  and  scale, 
deposit  of  sediment,  external  corrosion,  internal 
corrosion,  and  defective  pressure  gauges. 

Ques.     Is  scale  all  of  one  kind  ? 

Ans.  No.  The  nature  and  hardness  of  the  scale 
depend  upon  the  kind  of  substance  held  in  solution 
and  suspension  by  the  water  in  the  boiler. 

Ques.  What  general  course  is  the  best  in  dealing  with  the 
sediment  ? 

Ans.  It  is  more  profitable  to  soften  and  filter  the 
water  than  to  trust  to  blowing  out  or  dissolving  the 
sediment  and  scale  after  it  is  there. 

Ques.    What  is  the  action  of  a  scum-cock  ? 

Ans.  Nearly  all  foreign  matter  held  in  solution  in 
water,  on  becoming  separated  by  boiling,  rises  to 
the  top  in  the  form  commonly  called  scum,  and  every 
boiler  should  be  provided  with  means  for  blowing 
out  water  from  the  surface  in  order  to  remove  the 
fine  particles  of  foreign  matter  floating  there  ;  as,  if 


QUESTIONS  AND  ANSWERS.  87 

not  removed  the  heavier  particles  will  be  attracted 
to  each  other  until  they  become  sufficiently  dense  to 
fall  to  the  bottom,  where  they  will  be  deposited  in 
the  form  of  scale. 

Ques.  Can  a  mixture  be  made  to  use  in  a  great  majority 
of  cases  of  scale. 

Ans.  One  that  has  been  strongly  recommended  is 
made  up  of  40  Ibs.  of  sal  soda,  to  which  is  to  be 
added  5  Ibs.  of  catichu  and  5  Ibs.  of  salamoniac — 
one  Ib.  of  the  mixture  to  be  added  to  each  barrel  of 
water  used,  until  the  scale  disappears,  when  the  use 
of  sal  soda  alone  is  all  that  is  necessary. 

Ques.  Can  one  preparation  be  made  that  will  be  beneficial 
in  all  cases  of  deposited  sediment  ? 

Ans.  No.  This  is  owing  to  the  variety  of  chemi- 
cal matter  contained  in  water,  and  the  varying 
quantities  existing  in  the  steam  generators,  to  say 
nothing  of  the  different  temperatures  in  which  the 
"  compound  "  may  be  expected  to  operate. 

Ques.  What  is  essential  in  the  design  of  a  boiler  in  ref- 
erence to  the  sediment  ? 

Ans.  It  is  absolutely  essential  to  the  successful 
use  of  any  boiler,  except  in  pure  water,  that  it  be 
accessible  for  the  removal  of  scale,  for,  though  a 
rapid  circulation  of  water  will  delay  the  deposit, 
and  certain  chemicals  introduced  into  the  water  may 
lessen  it,  yet  the  only  certain  cure  is  periodical  in- 
spection and  mechanical  cleaning. 


38  ENGINEERS'  EXAMINATIONS. 


Questions  and  Answers  relating  to  the  Steam 
Boiler. 

Ques.    What  are  the  principal  forms  of  steam  generators  ? 

Ans.  There  are  three,  stationary,  locomotive  and 
marine,  which  terms  explain  for  what  uses  they  are 
built. 

<Jues.    Name  some  of  the  boilers  which  come  under  the 

heading  of  stationary. 

Ans.  The  Horizontal  Plain  Cylinder;  the  Two 
Flue ;  the  Horizontal  Tubular ;  the  Water-tube ; 
the  Cornish  ;  the  Sectional,  etc. 

({lies.    Which  form  is  the  one  most  largely  in  use  ? 
Ans.     The  Horizontal  Tubular. 

Ques.    What  are  its  special  advantages  t 

Ans.  This  type  is  the  result  of  many  years  of 
experiments,  and  aside  from  a  liability  to  an  occa- 
sional explosion,  has  proved  itself  best  adapted  to 
the  wants  of  steam  users. 

Ques.    Name  some  of  its  special  "  points    of  advantage. 

Ans.  It  is  the  cheapest  in  construction  ;  it  is 
cylindrical;  it  encloses  the  greatest  volume  of  water 
and  steam  with  the  least  material ;  it  is  very  access- 
ible for  cleaning  out  and  it  resists  internal  and 
external  strains  with  equal  excellence. 


QUESTIONS  AND  ANSfrEES.  30 

Ques.  What  is  the  peculiar  difference  between  water  tube 
boilers  and  others? 

Ans.  The  fact  of  the  small  tubes  being  used  for 
holding  the  water — the  distinction  is  expressed  by 
denominating  the  older  type  'fire  tube "  boilers. 

Ques.  Name  the  advantages  claimed  for  water  tube  boil- 
ers. 

Ans.  The  principal  claim  for  superiority  is  that 
they  are  supposed  to  be  safe  from  disastrous  explo- 
sions. This  is  owing  to  the  small  size  or  diameter 
of  the  tubes  of  which  they  are  built.  2d. — They  are 
quick  "steamers."  3d. — Are  accessible  for  repairs 
and  cleaning  and  are  easily  transported — being  con- 
structed in  small  sections — and  easily  set  up. 

Ques.  What  are  the  known  disadvantages  of  the  water 
tube  system  ? 

Ans.  While  they  make  steam  quickly,  the  press- 
ure as  quickly  subsides,  owing  to  the  small  reserve 
in  the  water  space;  the  use  of  cast-iron  used  in  their 
construction  has  frequently  worked  badly  in  prac- 
tice and  they  are  said  to  be  more  liable  to  "  prime  " 
than  other  forms. 

Ques.    Has  any  particular  form  of  steam  boiler  proved 

itself  absolutely  the  best  ? 

Ans.  No.  Tests  prove  that  a  square  foot  of 
heating  surface  in  both  systems,  if  properly  set  and 
with  an  equally  good  draft,  evaporates  nearly  the 


40  XlfGlXEERS1  E^^MIN 


same   number   of   pounds   of   water  to   a   pound   of 
coal. 

Ques.  What  is  the  essential  peculiarity  of  the  marine 
boiler  ? 

Ans.  By  U.  S.  Law  all  marine  boilers  rnust  be 
constructed  so  that  they  are  fired  internally.  The} 
are  not  allowed  to  be  "  set  "  in  brick  work. 

Ques.  "What  is  the  essential  peculiarity  of  the  locomotive 
boiler  ? 

Ans.  In  that  it  has  the  steam  engine  attached  to 
it,  thus  making  it,  as  it  were,  a  combined  engine 
and  boiler,  which,  with  the  steam-blast  invented  by 
Geo.  Stevenson,  forms  as  near  a  live  thing  as  is 
known  in  the  world,  of  man's  creation. 


About  how  many  pounds  of  water  can  be  evapora- 
ted per  pound  of  coal  by  an  ordinary  boiler  ? 

Ans.  From  seven  to  eleven  pounds,  depending 
upon  the  quality  of  the  coal,  the  draught,  and  the 
thickness  of  incrustation  on  the  interior  of  the  boiler 
and  amount  of  soot  and  ashes  on  the  shell  and  in 
the  tubes. 

Qnes.     What  part  of  the  steam  boiler  is  the  strongest  ? 

Ans.  The  strength  of  a  boiler  is  only  that  of  its 
weakest  part;  hence  boiler  makers  are  always  study- 
ing methods  of  perfecting  the  structure  so  that  every 
portion  has  the  same  resistance. 

Ques.     What  is  the  great  cause  of  steam  boiler  explosions  j 


QUESTIONS   AND   ANSWERS. 


Ans.  Weakness  in  the  boiler  to  withstand  the 
pressure.  When  a  boiler  is  strong  enough  to  hold 
the  steam  it  will  not  explode. 

(Jues.    What  produces  this  weakness  ? 

Ans.  Generally  by  overheating  the  plates,  caused 
by  shortness  of  water.  When  the  sheets  are  heated 
to  a  certain  point  they  lose  their  power  of  cohesidn 
and  become  very  weak.  This  causes  them  to  bulge 
or  come  down  ;  and  where  the  pressure  is  suddenly 
increased  by  pumping  in  water,  an  explosion  takes 
place. 

Ques.  What  other  causes  can  you  name  which  are  liable 
to  produce  an  explosion  ? 

Ans.  Excessive  pressure,  beyond  the  limit  for 
which  the  boiler  was  designed  ;  by  bad  workman- 
ship in  punching  and  riveting  the  sheets  ;  by  bad 
material  used  in  the  construction  of  the  boiler ;  by 
the  collection  of  mud  and  scale  ;  and  by  bad  design 
in  which  the  boiler  may  not  be  properly  strengthened 
by  stays  and  braces. 

Ques.  Have  you  any  particular  "theory  '  as  to  boiler  ex- 
plosions ?* 


*A  press  despatch  from  Haverhill,  Mass.,  tells  of  a  hundred  horse  power 
ooiler  which  recently  sailed  into  the  air  like  a  sky  rocket,  paused  for  an 
instant,  then  exploded  with  a  deafening  report  and  a  concussion  which 
shook  the  city  like  an  earthquake,  and  great  pieces  of  iron  flew  in  all 
directions.  The  cause  of  this  phenomenon  is  said  to  have  been  that  the 
fireman  of  a  hoisting  engine  boiler  fired  up  at  a  time  when  the  boiler  cott- 
tained  an  insufficient  amount  of  water. 


42  ENGINEERS'  EXAMINATIONS. 

Ans.  No.  I  simply  consider  an  explosion  the 
natural  consequence  of  "letting  go"  of  the  forces 
locked  up  in  the  steam  and  hot  water,  when  sud- 
denly released  from  the  power  of  resistance  in  the 
generator — being  like  the  "popping"  of  corn,  where 
the  moisture  of  the  kernel  is  turned  into  confined 
steam  by  heat,  until  the  pressure  becomes  too  great, 
when  an  explosion  takes  plane  which  shatters  the 
grain. 


QUESTIONS  AND  ANSWERS.  43 


Questions  and  Answers  Relating  to  Firing. 

Ones.    How  thick  should  be  the  body  of  coal  in  the  fur 
nace? 

Ans.  The  thickness  of  fire  to  be  carried  depends 
altogether  on  the  draught.  If  the  draught  is  strong 
it  should  be  heavier  than  when  it  is  weak,  and  a 
bituminous  (soft)  coal  fire  should  be  thicker  than 
one  of  anthracite  (hard)  coal.  For  hard  coal  three 
to  six  inches  should  be  the  depth,  and  for  soft  coal 
five  to  eight  inches. 

(Jues.    How  should  the  coal  be  spread  ? 

Ans.  It  should  be  kept  spread  evenly  all  over  the 
grate,  and  not  allowed  to  burn  in  holes,  leaving  the 
bars  bare,  as  the  cold  air  will  rush  in  and  chill  the 
heating  surface. 

Ques.    What  is  the  proper  way  to  clean  a  fire  ? 

Ans.  Take  a  hoe  and  push  the  upper  part  of  the 
fire  back,  leaving  the  clinkers,  ashes,  etc.,  on  the 
grate  ;  then  pull  the  ashes,  etc.,  out  with  the  hoe. 
To  clean  the  back  end  of  the  grate,  you  pull  the 
good  fire  forward  again,  and  draw  the  clinkers  and 
ashes  of  the  back  end  over  the  fire,  and  into  the  ash- 
pan.  Having  cleaned  it,  you  must  spread  the  fire 
evenly  all  over  the  grate,  and  then  cover  it  over  with 
fresh  coal,  but  not  too  heavily.  Care  must  be  taken 
with  anthracite  coal,  not  to  let  the  fire  burn  too  low 


44  ENGINEERS'  EXAMINATIONS. 

before  cleaning  it,   or  else  you   will    not    have    fire 
enough  left  to  cover  the  grate,  and  it  will  die  out. 

(Jues,     Can  you  add  anything  else  about  firing  ? 

Ans.  Whatever  is  done  to  a  fire  should  be  done 
quickly,  and  the  furnace  door  be  kept  open  no  longer 
than  necessary.  No  two  fires  should  be  cleaned  at 
the  same  time.  A  soft  coal  fire  needs  breaking  up 
at  short  intervals,  as  it  has  a  tendency  to  amalga 
mate,  or  crust  over  on  top  ;  but  a  hard  coal  should 
not  be  broken  up  with  the  bar.  All  that  is  necessary 
to  clean  it  of  ashes  is  to  run  the  slice  bar  over  the 
grate,  and  withdraw  it  without  breaking  up  the  fire. 

Ques.  In  case  of  a  fire  threatening  the  destruction  of  the 
whole  establishment,  what  is  the  first  thing  to  be  done  ? 

Ans.  The  fire  under  the  boilers  should  be  drawn, 
and  the  safety  valves  propped  open,  so  that  no  explo- 
sion may  take  place  after  the  place  has  been  left,  this 
being  done  for  the  safety  of  the  engineers,  firemen 
and  others. 

Ques.    How  would  you  fire  a  locomotive  ? 

Ans.  I  would  distribute  the  coal — after  the  fire 
is  well  started — evenly  in  a  strip  about  a  foot  wide, 
along  the  side-sheets  and  in  the  corners,  being  care- 
ful that  there  are  no  holes  along  the  side-sheets  and 
in  the  corners.  This  leaves  a  strip  across  the  fiire- 
box,  from  the  fire-door  to  the  flue-sheet,  that  1  do 
not  put  any  coal  on. 

Ques.    How  does  the  coal  get  into  the  center  ? 


QUESTIONS  AND  ANSWERS.  45 

Ans.  I  claim  that  the  engine  does  it.  When  the 
coal  is  put  into  the  fire-box  the  heat  soon  drives  the 
gas  arid  other  matter  out,  converting  it  into  coke, 
and  coke  being  very  light  the  draft  will  carry  it  to 
center  of  fire-box.  The  corners  and  along  the  sides 
being  a  little  higher  after  coal  has  been  put  in  also 
aids  the  draft.  The  fuel  furnished  to  this  strip 
being  coke,  it  takes  very  little  air  to  burn  it,  and  the 
draft  drawing  the  gas  from  the  sides  to  center  of 
box  gives  more  chance  for  air  and  gas  to  come  in 
contact  and  burn. 

Ques.     Has  this  method  been  tried  or  is  it  a  theory  ? 

Ans.  It  has  been  tried  and  it  is  claimed  that  a 
saving  of  10  per  cent,  can  be  made. 

Ques.     What  should  be  the  first  aim  in  firing  ? 

Ans.  To  keep  an  even  pressure  on  the  boiler; 
to  adjust  the  firing  to  the  work  demanded  of  the 
engine. 

Ques.    What  other  general  rule  would  you  recommend  ? 

Ans.  To  handle  the  fires,  the  water  supply  and 
the  management  of  the  steam  without  sudden 
changes — allowing  always  a  sufficient  time  for  the 
different  forces  to  adjust  themselves  to  their  changed 
conditions. 


46 


ENGINEERS'  EXAMINATIONS. 


Questions  and  Answers  Relating  to  the  Cir- 
culation of  Water  in  a  Boiler. 


(Jues.  What  is  circulation  of  water  in  a 
boiler  ? 

Ans.  When  a  body  of  water  is 
heated  through  the  shell  of  a  boiler  a 
movement  takes  place,  and  the  heated 
particles  rise  to  the  top,  and  the 
cooler  particles  from  above  take  their 
place.  These  particles  of  water  do 
not  move  the  same  in  all  parts  of 
the  boiler,  in  some  portions  the 
movement  will  be  upward  and  in 
other  portions  downward,  and  in  this 
way  the  circulation  in  a  boiler  is  pro- 
duced. 

Ques.  What  particular  force,  or  energy, 
produces  this  movement  ? 

Ans.  Heat.  The  movement  of 
the  water  is  due  to  the  difference  in 
weight  of  the  particles.  The  water  at 
the  bottom  becomes  heated  and 
expands  in  consequence,  and  thus 
becoming  somewhat  lighter  than  the 
colder  particles,  is  forced  upward  by 
the  greater  density  of  the  cold  water 
above.  In  this  way,  too,  heat  is 
diffused  throughout  the  whole  body 
of  water  in  the  boiler. 


NOTE.— The  cut  shows  the  ebullition  as  it  goes, 
on  in  a  restricted  space. 


QUESTIONS  AND  ANSWERS.  47 

Ques.  Is  there  any  other  force  which  comes  into  action 
to  produce  the  circulation  ? 

Ans.  Yes.  The  columns  of  rising  steam  obtain 
great  physical  power,  violently  and  mechanically 
forcing  upwards  the  water  which  comes  in  their 
way. 

Ques.  Is  it  important  to  provide  for  these  rising  globules 
or  columns  of  steam  ? 

Ans.  The  flues  and  water  spaces  in  boilers  should 
be  so  arranged  as  to  provide  a  regular  and  unre- 
stricted circulation  of  both  the  downward  and  the 
upward  flow  of  hot  water  and  the  upward  rush  of 
the  steam. 

Ques.    Where  does  the  movement  of  the  particles  begin  ? 
Ans.     At  the  bottom. 

Ques.  In  what  department  is  the  knowledge  of  the  circu 
lation  of  heated  water  most  needed  ? 

Ans.  In  the  steam  and  hot  water  heating-  of 
buildings  and  work  shops,  etc. 


ENGINEERS'  EXAMINATIONS. 


Questions  and  Answers  Relating  to  Combus 
tion  of  Coal. 

Qnes.    What  does  the  word  combustion  mean  ? 
Ans.     To  burn,  to  kindle,  to  light. 

(jues.  Before  any  burning  of  coal  can  take  place  what 
must  occur  ? 

Ans.  The  coal  must  suffer  the  preparatory  pro- 
cess of  decomposition.  It  must  be  dissolved  in 
minute  particles  of  gas  or  coke.  In  the  combustion 
of  bituminous,  or  soft  coal,  there  are  two  distinct 
operations,  viz.:  the  distilling  of  the  gas  and  its 
combustion,  and  the  combustion  of  the  remaining 
solid  carbon  or  coke. 

Ques.    What  part  is  first  consumed ': 

Ans.  The  gas.  This  unites  with  the  oxygen  of 
the  air  and  burns  first. 

Ques.    What  burns  next  ? 

Ans.  The  coke,  in  the  same  way  as  the  gas,  i.  e., 
the  particles  of  the  coke  unite  with  the  oxygen  of 
the  air  and  it  in  turn  is  consumed. 

Ques.    How  is  the  gas  ignited  ? 

Ans.  The  heat  under  which  the  gas  itself  distills 
will  always  ignite  it  if  the  due  admixture  of  air  is 
immediately  obtained. 


QUESTIONS  AND  ANSWERS.  49 

(Jues.  Is  it  necessary  to  have  air  admitted,  and  if  so. 
which  is  the  best  manner  of  supplying  it  to  the  fuel  in  order 
that  it  may  be  most  effectively  consumed  ? 

Ans.  Air  is  absolutely  essential  and  is  best 
admitted  through  the  grate-bars  to  the  furnace  in 
innumerable  fine  jets,  since  gas  and  air  mix  only 
gradually.  Air  in  bulk  mixes  only  superficially  with 
gas,  and,  by  abstracting  heat,  cools  the  furnace. 
Gases  to  be  thoroughly  burned  in  the  furnace  must 
be  intercepted  at  the  start,  else  the  combination, 
which  is  at  best  gradual,  will  not  be  completed  in 
season. 

(Jues.  As  to  air  entering  the  furnace  above  the  burning 
fuel,  is  it  desirable  ? 

Ans.  A  proper  amount  of  air  (oxygen)  entering 
the  furnace  above  the  fuel  in  small  quantities  assists 
somewhat  in  the  combustion  of  the  gases,  but  a 
great  quantity  is  detrimental  and  injurious. 


Is  there  any  other  theory  about  this  ? 

Ans.  Yes.  It  is  claimed  that  if  the  fuel  is  not 
put  on  the  grate  in  too  thick  a  layer  no  necessity  for 
such  introduction  of  air  is  necessary. 

Ques.  In  supplying  air  to  the  furnace  is  it  an  advantage 
to  have  it  heated  ? 

Ans.  Probably  not.  There  are  certain  practical 
objections  to  heating  the  air  supply  for  boiler  fur- 
naces. First,  for  every  480  degrees  Fahr.  of  added 
heat  its  bulk  is  enlarged  by  the  amount  of  its 


50 


ENGINEERS'   EXAMINATIONS. 


original  volume,  so  that  at  3000  degrees,  the  heat  of 
the  interior  of  the  furnace,  it  has  six  times  its 
original  volume.  It  is,  consequently,  more  unman- 
ageable; and  as  its  contained  oxygen  retains  the 
same  weight,  its  mixture  with  the  gas  becomes  more 
difficult,  while  when  mixed  it  can  only  do  the  same 
work  as  before.  It  would  be  much  better  to  con 
dense  the  air  than  to  expand  it.  Next,  if  heated  by 
passing  through  flame  or  over  burning  coal,  the  air 
will  be  robbed  of  a  greater  or  less  part  of  its  vital 
oxygen.  This  is  a  positive  loss. 


TABLE  OF  HEAT  OF  COMBUSTION. 


Combustible. 

Total  units  of 
heat  of  com- 
bustion per  Ib. 

Lbs.  of  water 
evaporated 
from  and  at 
212°. 

Hydrogen    

62,032 

64-2 

Carbon    burned    to    carbonic 

4,400 

4-55 

Carbon    burned    to    carbonic 
acid 

14,500 

15-0 

14,700 

15-2 

Bituminous  coal  

14,000 

14-5 

Coke                      

13,640 

14-1 

14,000 

14-5 

20,360 

21  0 

20,800 

21-5 

Oak  wood  (dried)  

7,700 

8 

QUESTTONS   AND   ANSWERS.  5J 

Qncs.    What  is  the  combustion  chamber  ? 

Ans.  It  is  that  space  under  the  boiler  where  the 
burning  or  combustion  of  the  fuel  takes  place. 

(Jues.  What  is  the  first  essential  in  the  construction  of  the 
sombustion  chamber  ? 

Ans.  It  must  be  large  enough,  as  the  fuel  before 
burning  must  be  enormously  expanded.  It  is  said 
that  a  lump  of  coal  the  size  of  a  man's  fist  or  less, 
must  be  expanded  so  that  it  occupies  a  cube  meas- 
uring nine  feet  each  way — hence  the  combustion 
chamber  must  be  very  large  indeed  compared  with 
the  space  occupied  by  the  solid  fuel  as  it  is  placed 
upon  the  grate  bars. 

Ques.  Give  the  successive  processes  of  combustion  as 
developed  in  making  a  coal  fire. 

Ans.  It  is  a  progressive  process,  i,  The  match, 
by  friction,  ignites  the  phosphorus  on  its  tip,  at  150° 
Fahrenheit ;  2,  this  sets  fire  to  the  sulphur  at  500°  ; 
3,  this  causes  the  soft  wood  of  the  match  to  burn  at 
800°  ;  4,  which  in  turn  fires  the  coal  at  1,000°; 
5,  at  this  point  the  coal  unites  with  the  free  oxygen 
of  the  air  and  carries  the  furnace  heat  up  to  4,000°, 
more  or  less,  and  completes  the  process 

Ques.    What  is  a  combustible  ? 

Ans.  Something  which  burns — coal,  oil,  wood, 
are  combustibles. 


ENGINEERS'  EXAMINATIONS. 


Questions  and  Answers  Relating  to  tlie  Con- 
struction and  Strength  of  Steam  Boilers. 


Qnes.    Of  what  material  are  boilers  built  ? 

Ans.  Of  sheet  steel,  as  owing  to  furnace  im- 
provements this  superior  metal  can  now  be  made 
cheaper  than  wrought  iron,  and,  moreover,  mild  steel 
has  proved  to  be  the  best. 

Ques.  What  is  the  process  of  joining  the  sheets  together 
called? 

Ans.  Riveting,  although  in  certain  cases  the 
sheets  have  been  welded,  and  in  time  this  may 
become  the  general  rule. 

Ques.    What  are  the  two  principal  kinds  of  riveting  ei 

Ans.  Two — single  and  double.  Single  riveting 
for  the  girth  seams  of  the  boiler  and  double  for  the 
lengthwise  seams.  In  the  latter  the  rivets  form  a 
zig-zag  line  at  each  joint  or  seam. 

NOTE.— THE  AMERICAN  BOILER  MAKERS  standard  of 
strength  for  steel  boiler  plate  is  as  follows :  "  Tensile  55,000  to  65,000 
Ibs.  per  square  inch  of  section  ;  elongation  in  8  inches  20  per  cent,  for 
plates  %  inch  thick  and  under ;  22  per  cent,  for  plates  %  inch  to  % 
inch ;  25  per  cent,  for  plates  %  inch  and  under.  Specimen  piece  must 
bend  back  on  itself  (cold)  without  fracture ;  for  plates  over  %  inch 
thick  specimen  must  withstand  bending  180°  (^$  way)  round  a  mandril 
1^  times  the  thickness  of  the  plate.  Chemical  requirements :  phos- 
phorus not  over  .040  per  cent.;  sulphur  uot  over  .030  per  cent." 


QUESTIONS  AND  ANSWERS. 


Ques.    What  size  rivets  are  used  in  joining  the  sheets  ? 

Ans.  They  are  long  enough  to  bend  over  and 
form  a  head,  and  of  a  diameter  suited  to  the  different 
thickness  of  the  plates,  f£,  ^,  fa,  according  to  the 
specifications  for  making  a  boiler  when  it  is  first 
constructed. 

Ques.  What  is  the  thinnest  sheet  which  should  be  used  in 
a  boiler  ? 

Ans.  One-quarter  of  an  inch  ;  this  is  the  thinnest 
which  can  be  caulked  to  advantage. 

Ques.    What  is  caulking  ? 

Ans.  This  is  the  closing  of  the  seams  after  the 
riveting  has  been  done,  and  is  executed  by  a  blunt 
chisel ;  when  the  work  is  done  by  a  round  nosed 
chisel  it  is  called  "fullering." 

Ques.    Is  a  thin  plate  better  than  a  thick  one  ? 

Ans.  It  is  said  by  practical  boiler  makers  that 
the  thinner  the  sheet — so  long  as  it  affords  sufficient 
strength — the  longer  it  will  last  under  the  varying 
strains  to  which  a  steam  boiler  is  subjected,  and  that 
the  caulking  will  also  last  longer  and  better. 

Ques.    What  are  the  flanges  of  a  boiler  ? 

Ans.  They  are  those  parts  which  are  bent  over ; 
this  is  called  flanging  ;  for  example,  the  heads  of  the 
tubular  boiler  are  turned  over  to  be  joined  to  the 
shell,  or  body  sheets. 


64  ENGINEERS'  EXAMINATIONS. 

Ques,    What  are  the  "  lugs  "  of  a  boikr  ? 

Ans.  The  lugs  are  the  castings  riveted  on  each 
side  of  the  boiler  which  support  or  "  lug  "  it.  There 
are  commonly  three  or  four  lugs  on  each  side. 

Ques.  Suppose  the  water  should  fall  below  the  lowest 
gauge-cock,  what  is  to  be  done  ? 

Ans.  If  the  fires  are  light,  they  should  at  once  be 
hauled;  but  should  they  be  heavy,  the  better  plan  is 
to  smother  the  fire  with  fresh  coal,  dust,  or  ashes 
out  of  the  ash-pans. 

Ques.  What  are  the  two  principal  methods  of  testing 
steam  boilers  ? 

Ans.     There   are   two   methods   in   general  use, 

known  as  the  "  hydrostatic  test  "  and  "hammer  test." 
The  former  test  consists  in  filling  the  boiler  with 
water,  and  then  with  a  hand  force-pump  raising  the 
pressure  up  to  that  which  it  is  supposed  the  boiler 
will  stand.  The  "hammer  test"  is  applied  in  all 
accessible  parts  of  the  boiler,  such  as  the  shell 
flues,  and  braces,  by  tapping  with  a  light  hammer. 

Ques.    What  is  meant  by  the  pitch  line  of  riveted  work  ? 

Ans.  The  distance  from  center  to  center  of  the 
rivet. 

Ques.  How  far  from  the  edge  of  a  sheet  may  a  rivsb  hole 
be  properly  made  ? 

Ans.  A  distance  equal  to  the  diameter  of  the 
rivet  hole,  i.  e.,  the  space  between  the  edge  of  the 


QUESTIONS  AND  ANSWERS.  55 

rivet  hole  and  the  edge  of  the  sheet  must  equal  the 
diameter  of  the  rivet. 

(Jues.  Does  the  removal,  or  punching  out,  of  the  metal 
for  the  rivet  hole  weaken  the  plates  and  consequently  the 
boiler  ? 

Ans.     Yes. 

(Jues.  What  is  the  rule  as  to  pitch  of  the  rivets  in  view  of 
this  weakening  ? 

Ans.  There  shall  be  the  same  strength  of  iron 
between  the  rivets  as  there  is  in  the  rivets  themselves. 

Ques.  What  is  the  most  advantageous  thickness  of  boiler 
plates  ? 

Ans.  It  has  been  found  by  experience  that  a 
thickness  of  about  fe  of  an  inch  is  the  most  favor- 
able to  sound  riveting  and  caulking  of  boiler  plates; 
and  they  are  seldom  made  much  thicker  or  thinner 
than  that  thickness;  if  more  strength  is  needed  in  a 
boiler  it  is  better  to  reduce  the  diameter  of  the  shell 
than  to  increase  the  thickness  of  the  plates. 

Qncs.    Is  it  usual  to  make  the  heads  thicker  than  the  shell  I 

Ans.  Yes.  Where  the  shell  is  fo  the  ends  are 
made  ^  inch,  and  in  that  proportion, 

({110$.  What  is  the  name  of  the  round  plate  which  forms 
the  ends  of  a  tubular  boiler  ? 

Ans.  The  tube  plate,  because  in  it  the  ends  of 
the  tubes  are  riveted  and  beaded- 


56  ENGINEERS'  EXAMINATIONS. 

(jues.  How  many  principal  kinds  of  seams  are  there  in 
boilers  ? 

Ans.  The  "  lap  "  and  the  "  butt  "  joint,  the  names 
of  which  signify  the  way  in  which  the  bheets  are 
riveted. 

Ques,  How  do  you  ascertain  the  strength  of  a  riveted 
seam? 

Ans.  It  is  customary  to  multiply  the  tensile 
strength  of  the  metal  by  .70  or  TTTF  for  double 
riveted  longitudinal  seams  and  .56  for  single  riveted* 

Ques.    Give  an  example. 

Ans.  If  the  steel  plates  have  60,000  Ibs.  tensile 
strength  per  square  inch,  then  f^  of  the  square 
inch  would  be  22,500  Ibs. — multiplying  this  by. 70 
gives  15,750  pounds  as  the  strength  of  the  double 
riveted  seam. 

Or  multiplying  by  .56  it  gives  12,600  as  the 
strength  of  the  single  riveted  seam. 

(Jues.  How  does  the  strength  of  a  seam  compare  to  that 
of  a  solid  sheet  ? 

Ans.  The  custom  is  roughly  to  consider  the 
strength  of  the  single  riveted  seam  to  be  one-half 
that  of  the  solid  sheet  and  the  double  riveted  three- 
fourths. 

(Jues.  When  inspectors  figure  the  allowable  pressure  upon 
a  boiler  how  do  they  proceed  ? 


QUESTIONS  AND  ANSWERS.  C? 

Ans.  They  take  the  strength  of  the  seam  and  the 
strength  of  the  weakest  plate.  They  also  figure  the 
size  and  pitch  of  the  rivet. 

Ques.  Can  you  give  a  short  rule  for  decennining  the 
strength  of  a  boiler  —  taking  the  weakest  sheet  ? 

Ans.  Multiply  the  thickness  of  the  weakest  plate 
in  the  boiler  by  its  tensile  strength  per  square  inch 
in  pounds,  and  divide  the  product  by  one-half  of  the 
diameter  of  the  boiler  in  inches,  and  multiply  the 
product  by  .56  for  single  riveted  longitudinal  seams 
and  by  .70  for  double  riveted  longitudinal  seams. 

Ques.  What  will  be  the  strength  of  a  boiler  with  ^  inch 
plates  of  50,000  Ibs.  tensile  strength,  double  riveted,  and 
boiler  40  inches  in  diameter  ? 

Ans.  One  quarter  plate  gives  #  of  the  strength 
of  the  square  inch  of  section  =  12,500  ;  divide  this 
by  y2  (of  40  in.  diam.)  20  =  625  Ibs.  This  would  be 
for  a  solid  sheet;  for  double  riveted  multiply  by 
Ibs.  total  strength 


Ques.  Would  inspectors  allow  this  as  the  pressure  to  be 
carried? 

Ans.  No,  for  they  have,  by  law  and  custom,  "  a 
factor  of  safety,"  which  only  allows  one-fourth  to 
one-sixth. 

Ques.  With  a  factor  of  six,  now  much  wSfi  be  allowed  in 
this  case? 

Ans.    About  75  Ibs, 


ENGINEER'S  EXAMINATIONS. 


Ques.    With  a  factor  of  five,  how  much  ? 

Ans.  About  85  Ibs. — the  figure  being  approxi- 
mated by  the  inspector — if  needed. 

(Jues.    What  have  you  to  say  as  to  grate  bars  ? 

Ans.  When  the  furnace  is  more  than  four  (4)  feet 
long  the  bars  should  be  put  in  in  two  lengths,  but  if 
it  is  four  feet  or  less  in  length,  one  bar  will  suffice, 
in  which  case  only  two  bearing  bars  will  be  required. 
When  a  center  bearing  bar  is  used  for  two  lengths, 
it  should  be  made  like  a  double  grate-bar — that  is, 
with  an  opening  or  air-space  in  the  middle.  Grate- 
bars  when  hot  expand  considerably,  and  therefore 
they  should  not  be  put  in  tight,  or  too  close  together, 
but  should  have  end  and  side  play,  otherwise  they 
will  bend  and  twist  out  of  shape  and  soon  be 
destroyed. 

Ques.  Does  heating  a  boiler  in  the  regular  "firing" 
weaken  or  strengthen  it  ? 

Ans.  It  strengthens  it,  because  wrought  iron 
heated  to  a  point  less  than  600°  Fahr.  increases  in 
strength,  and  as  at  200  Ibs.  pressure  on  the  boiler  per 
square  inch  the  temperature  is  less  than  400°,  it  fol- 
lows that  it  grows  stronger.* 


*NOTE.— Under  a  test  it  has  been  shown  that  the  strength  of  Iron 
Increases  up  to  570°,  when  it  begins  to  decrease  with  the  added  heat. 
At     32°  it  was  56,000  Ibs.  per  square  inch. 
it    570o  u     »»     66,500    "      "          **          ** 
i.    23QO  »»     «     55^000    «      •«          »*          •* 
u  1050°  "     "     32,000     "      -»          •*          " 
w  1240°  "     "     32,000    **      **          w          ** 
»»      9%OUO    w      **         **         *» 


QUESTIONS  AND  ANSWERS.  59 

Questions  and  Answers  Relating  to  the 
Physical  Properties  of  Steam. 

Ques.    What  is  steam  ? 

Ans.  Steam  is  an  invisible  elastic  fluid,  or  water, 
brought  to  the  state  of  gas  by  the  application  of 
heat. 

Ques.    What  is  live  steam  ? 

Ans.  Live  steam  is  steam  under  pressure  and  ready 
to  do  work  through  the  agency  of  the  steam  cylinder, 
or  for  heating,  boiling,  etc. 

Qnes.    What  is  dead  steam  ? 

Ans.  Dead  steam  is  the  opposite  of  live  steam 
—such  as  exhaust  steam  or  the  vapor  which  fills  the 
steam  generator  before  there  is  any  pressure. 

Ques.    What  is  dry  steam  ? 

Ans.  Dry  steam  is  that  which  holds  no  water  in 
suspension.  High  pressure  steam  has  been  proved 
by  experiment  to  be  dry  like  dust. 

(Jties.  Why  is  stea*m  invisible  except  as  it  is  being  con- 
densed ? 

Ans.  Like  many  other  gases  it  possesses  the 
quality  of  invisibility. 

(Jues.    What  is  saturated  steam  ? 

Ans.  This  is  steam  under  pressure  in  contact 
with  water  in  the  boiler;  its  condensing  point  agrees 
with  the  boiling  point  of  the  water  on  which  it  rests 


60  ENGINEERS'  EXAMINATIONS. 

Ques.  What  are  the  constituents  of  which  steam  is 
formed  ? 

Ans.  It  contains  the  same  elements  as  the  water 
of  which  it  is  formed,  /.  e.,  two  gases,  oxygen  and 
hydrogen. 

Ques.  In  what  proportions  do  these  exist  in  water  and 
steam  ? 

Ans.  Two  volumes  of  oxygen  and  one  volume 
of  hydrogen,  but  in  weight  che  hydrogen  is  the 
lightest. 


Ques.  Are  the  oxygen  and  hydrogen  (gases)  found  in  coal 
the  same  substances  as  those  described  in  above  answer  Y 

Ans.  Yes,  because  these  two  are  simple  bodies  in 
themselves,  while  found  in  thousands  of  combina- 
tions with  other  original  elements. 

Ques.  If  water  is  confined  in  a  boiler,  and  the  vessel  en- 
tirely full,  and  then  heated  to  a  high  temperature,  will  there 
be  any  steam  formed. 

Ans.  No,  because  steam  requires  space  in  which 
to  expand. 

Ones.  How  many  times  is  water  expanded  in  being 
changed  into  steam  at  the  pressure  of  the  atmosphere  ? 

Ans.  Into  sixteen  hundred  and  sixty-nine  timei 
the  volume  ;  or  roughly,  1,700  times. 

Ques.  What  occurs  in  the  expansion  when  a  pressure  i* 
placed  upon  the  boiler  ? 


QUESTIONS  AND  ANSWERS.  61 

Ans.  It  expands  according  to  the  pressure.  The 
greater  the  pressure  the  less  the  volume.  This  is 
given  in  tables  carefully  computed;  at  a  pressure  of 
150  Ibs.  to  the  square-inch  the  volume  is  reduced 
to  284  times,  and  at  300  Ibs.  pressure  to  96  times. 

Ques.    What  is  superheated  steam  ? 

Ans.  When  steam  is  separated  from  the  water 
over  which  it  was  formed,  and  afterwards  re-heated 
to  a  higher  temperature  than  the  water  and  steam 
it  becomes  superheated  steam. 

Ques.  Which  is  the  heaviest,  a  pound  of  steam  or  a  pound 
of  water  ? 

Ans.  A  pound  of  steam  is  the  same  in  weight  as  a 
pound  of  water.  It  is  good  form  to  say  that  the 
engine  uses  "  so  many  pounds  of  steam  "  instead  of 
so  many  pounds  of  water. 

Ques.  Which  is  the  heaviest  at  atmospheric  pressure, 
steam  or  air  ? 

Ans.  Steam  is  the  lightest,  because  it  always 
rises.  It  is  about  two-thirds  the  weight  of  air.  In 
the  tables  it  is  put  down  at  .625. 

Qucs.  When  air  is  confined  with  steam  inside  the  boiler 
which  is  then  the  heaviest  ? 

Ans.  Both  being  under  more  than  atmospheric 
pressure  (14  Ibs,  to  the  inch),  air  will  be  the  lightest 
because  its  rate  or  ratio  of  compression  is  greater 
/.  e.,  steam  compresses  more  readily  than  air. 


62  ENGINEERS'  EXAMINATIONS. 

Ques.  Is  air  confined  in  the  boiler  with  steam  considered 
hurtful  or  dangerous  ? 

Ans.  No,  as  with  the  immense  volume  of  steam 
being  formed  and  used  through  the  engine  it  soon 
passes  off.  Some  engines  are  altogether  operated 
by  compressed  air. 

Ques.    What  is  wet  steam  ? 

Ans.  Steam  full  of  spray — or  with  water  mechan- 
ically suspended  in  the  steam. 

Ques.  What  is  the  difference  between  high  and  low  pres- 
sure steam  ? 

Ans.  High  pressure  steam  is  commonly  under- 
stood to  mean  steam  used  in  high  pressure  engines, 
and  low  pressure  steam  is  that  used  at  low  .pressure 
in  condensing  engines,  heating  apparatus,  etc.,  at  15 
Ibs.  pressure  or  under. 

Qnes.     At  what  temperature  does  water  evaporate  ? 
Ans.    Water  evaporates  at  all  temperatures  above 
freezing  point,  and  boils  at  212°. 

Ques.    What  is  absolute  pressure  of  steam? 

Ans.  Absolute  pressure  is  its  pressure  estimated 
or  reckoned  above  vacuum  ;  or  the  steam  pressure 
shown  by  the  ordinary  steam  gauge  with  the  pres- 
sure ot  the  atmosphere  added  ? 

Ques     What  is  initial  pressure  ? 

Ans.  Initial  pressure  is  that  in  the  cylinder  of 
an  engine  at  the  beginning  of  the  forward  stroke  of 
the  piston. 


QUESTIONS  AND  ANSWERS.  63 


Ques.    What  is  terminal  pressure  ? 

Ans.  Terminal  pressure  is  that  which  would  be 
in  the  cylinder  at  the  end  of  the  stroke  of  the  piston 
if  the  exhaust  valve  did  not  open  until  the  stroke 
was  finished  ? 

Ques.    What  is  wire  drawing  ? 

Ans.  Wire  drawing  is  the  operation  of  reducing 
the  pressure  of  steam  between  the  boiler  and 
the  cylinder  ? 

Ques.  Does  the  change  from  water  to  steam,  by  the  ap- 
plication of  heat,  affect  the  relation  of  the  particles  of  the 
different  fluids  ? 

Ans.  As  water,  the  particles  are  strongly  co- 
hesive, but  as  steam  the  particles  are  repellent.  It 
is  this  repellant  force  existing  among  the  infinitely 
small  atoms  of  steam  which  appears  to  give  the 
energy  to  the  mass  of  steam  and  renders  it  service- 
able. 

Ques.  Does  this  change  mean  anything  looked  at  as 
power  ? 

Ans.  The  fluid,  as  water,  is  inexpansive,  but  the 
change  to  steam  gives  it  energy  or  the  ability  to  do 
work  by  the  reason  of  its  great  expansive  or  elastic 
tendency. 

Ques.    Has  the  process  we  call  boiling  anything  to 

do  with  steam  ? 

Ans.  Yes.  Boiling  is  caused  by  the  formation  of 
Steam  particles. 


64  THE  STEAM  ENGINE. 


THE  STEAM  ENGINE. 


While  machines  may  vary  greatly  in  different  particulars, 
the  laws  of  matter  are  the  same,  and  will  remain  unchanged 
for  all  time  ;  hence  it  must  be  borne  in  mind  that  success  in 
the  design,  care  and  management  of  an  engine,  no  matter 
what  may  be  its  size,  kind  or  use,  can  only  be  achieved  by 
a  close  observance  of  the  fundamental  laws  which  govern 
the  formation  and  use  of  steam. 

All  steam  engines  may  be  divided  into  two  great  classes, 
according  as  they  are  or  are  not  provided  with  apparatus  for 
condensing  the  steam.  These  classes  are:  1,  condensing,  or 
low  pressure  engines;  2,  non-condensing,  or  high  pressure 
engines. 

Engines  of  the  second  class  are  on  the  whole  less  econom- 
ical of  fuel  than  those  of  the  first  class,  but,  having  fewer 
parts  and  occupying  less  space,  they  are  much  used  where 
simplicity  and  compactness  are  considered  of  more  impor- 
tance than  economy  of  fuel. 

A  second  mode  of  classing  steam  engines  is  founded  on  the 
way  in  which  steam  acts  on  the  piston,  and  is  as  follows : 

1.  Single  acting  engines^  in  which  the  steam  performs  its 
work  by  its  action  on  one  side  of  the  piston  only. 


THE  STEAM  ENGINE.  65 

2.  Double  acting  engines,   in    which    the  steam  exerts 
energy  on  either  side  of  the  piston  alternately. 

3.  Rotatory  engines,  in  which  the  steam  drives  a  revolving 
piston  round. 

A  third  mode  of  classification  distinguishes  engines  into — 

1.  Non-rotative,  in  which  no  continuous  rotation  is  pro- 
duced, as  in  single  acting  pumping  engines,  steam  hammers, 
etc. 

2.  Rotative  engines,  in  which  the  motion  is  finally  com- 
municated to  a  continuously  rotating  shaft. 

Rotative  engines  are  now  the  most  common.  Non -rotative 
engines  are  exceptional. 

A  fourth  mode  of  classing  engines  is  founded  on  their 
purposes,  as  follows : 

1.  Stationary  engines,  such  as  those  used  for  pumping 
water,  for  driving  manufactory  machinery,  etc. 

2.  Portable  engines,  which  can  be  moved  from  place  to 
place  but  are  stationary  when  at  work. 

3.  Marine  engines,  for  propelling  vessels. 

4.  Locomotive  engines,  for  propelling  vehicles  on  land. 

Stationary  engines  exist  of  all  the  classes  belonging  to  the 
three  previous  modes  of  classification.  Portable  engines  are 
usually  non-co£densing,  to  save  space,  and  to  adapt  them  to 
situations  where  injection  water  cannot  be  obtained  in  suffi- 
cient quantity.  Most  of  them  are  also  double  acting  and 
rotative.  Marine  engines  are  in  general  condensing,  double 
acting  and  rotative.  Locomotive  engines  are  almost  all  non- 
condensing,  and  are  all  double  acting  and  rotative. 


66  THE  STEAM  ENGINE* 

In  the  selection  of  an  engine  there  are  six  points  to  ob- 
serve relating  to  it  before  its  purchase : 

L    Its  simplicity. 

H.    Its  strength. 

HI.    Durability  and  least  wear. 

IV.     Economy  in  the  use  of  steam. 
V.     Regularity  of  speed. 

VL     Fitness  for  its  work. 

Any  intelligent  engineer  has  observed  that  his  engine  has 
an  individuality  not  possessed  by  any  other,  and  a  personal 
acquaintance  with  its  peculiarity  is  quite  necessary  to  obtain 
the  best  results  from  it.  This  remark  applies  with  equal  or 
greater  force  to  the  steam  boiler  and  steam  pump,  and  the 
successful  engineer  or  fireman  is  the  one  quickest  to  under- 
stand "the  points  "  of  his  machine. 

Great  progress  has  been  made  in  the  art  of  engine  building 
since  the  introduction  of  electric  light  and  power  plants  and 
every  indication  is  that  still  greater  perfection  will  be  gamed.* 

*NOTE.— In  marine  engineering  the  progress  in  coal  economy  has 
been  wonderful  as  may  be  seen  from  the  following  table : — 

Pressure  of  steam  Consumption  of 

Year,  by  boiler  gauge  coal  per  I.  H.  P 

per  sq.  In.  per  hour. 

1S30  2  to  3  Ibs.  9.0  Ibs, 

1840  8  "  6.5 

1850  14  "  4.0 

1860  30  "  ao 

1870  40  to  40  "  2.6 

1880  TO  to  80  "  22 

1886  150  to  160  "  1.6 

1889  175  "  L4 

1890  200  "  LA 


QUESTIONS  AND  ANSWERS.  67 

Questions  and  Answers  Relating  to  the 
Steam  Engine. 


Ques.  Along  what  lines  has  the  latest  development  of 
steam  engines  been  carried? 

Ans.  There  is  a  steady  progress  in  the  produc- 
tion of  stronger,  more  rigid  engines,  using  higher 
steam  pressure  and  to  run  at  higher  speeds  than 
now.  The  automatic  cut-off  is  rapidly  displacing 
the  old  throttling  engine,  and  much  attention  is 
paid  to  condensers  and  the  compounding  of  steam. 

Ques.  What  cause  has  operated  to  produce  the  necessity 
for  stronger  and  more  rigid  engines  and  larger  bearing  sur- 
face? 

Ans.  The  higher  speeds — 100  revolutions  per 
minute  being  now  not  uncommon.  A  speed  of  160 
revolutions  per  minute  or  1120  ft.  piston  speed  has 
been  recorded  in  a  20x42  in.  Corliss  engine. 

Ques.  Which  ^hgine  holds  first  rank  as  the  most  econom- 
ical and  generally  satisfactory  type? 

Ans.     The  Corliss. 

Ques.  In  what  cases  has  the  compounding  in  the  Corliss 
engine  been  found  advantageous? 

Ans.  Where  large  power  is  demanded.  In 
smaller  powers  the  ordinary  simple  expansion  engine 
has  been  found  sufficiently  advantageous. 


EXAMINATIONS. 


(Jues.  What  are  the  two  great  classes  into  which  engines 
are  divided? 

Ans.     Throttling  and  automatic. 

Ques.    Where  is  the  difference? 

Ans.  In  the  principle  of  regulation  in  supplying 
the  steam  from  the  boiler  to  the  engine  by  auto- 
matic or  throttling  valves. 

Ques.     Which  is  the  oldest  system? 

Ans.  The  throttling  principle  was  almost  uni- 
versal until  Corliss  introduced  his  automatic  cut-off 
engine,  which  he  made  an  immediate  success  by 
guaranteeing  certain  results  from  the  use  of  a  speci- 
fied amount  of  fuel. 

Ques.  What  is  the  advantage  of  the  automatic  cut-off  as 
claimed  by  engine  builders? 

Ans.  It  comes  from  the  fact  that  most  steam  en- 
gines are  subjected  to  variable  loads,  and  quite 
generally  some  difference  in  steam  pressure.  The 
economical  point  of  cut-off  varies  with  the  load, 
and  the  automatic  cut-off  governor  so  varies  the 
amount  of  steam  as  to  secure  the  best  results,  pres- 
sure being  constant 

Qnes.  In  what  places  are  the  throttling  valve  engines 
without  objection? 

Ans.  Where  there  are  but  little  variations,  either 
in  the  pressure  of  steam  or  in  the  duty  to  be  per- 
formed. 


QUESTIONS   AND   ANSWERS. 


Ques.     What  can  be  said  about  simplicity  in  an  engine? 

Ans.  It  is  always  a  point  of  great  importance  to 
build  an  engine  containing  the  least  number  of  parts 
and  the  simplest  elements  attainable  in  construction 
and  design,  such  as  the  form  of  frame  orbed,  piston 
head,  packing  rings,  cross-head,  guides,  connecting 
rod  ends,  valve  gear,  valves  and  regulating  appli- 
ances. 

(Jues.    What  about  the  strength  of  an  engine? 

Ans.  All  parts  should  be  so  proportioned  as  to 
insure  the  greatest  durability  and  to  prevent  tremors 
and  strains. 

(Jues.    What  about  the  point  of  durability? 

Ans.  The  least  variation  in  the  line  of  the  en- 
gine, a  slight  settlement  of  the  foundation,  unequal 
wear  of  a  bearing  or  failure  of  oil  to  flow  but  for  a 
moment,  will  cause  parts  to  heat,  wear  and  ulti- 
mately fracture  ;  hence  the  new  engine  should  be 
speeded  only  as  fast  as  will  enable  the  mechanism 
to  continue  its  work  with  the  least  wear  and  stress, 
thus  avoiding  the  error  (now  exposed)  that  the  rate 
of  speed  of  a  perfectly  constructed  engine  is  unlim- 
ited. 

(Jues.  What  can  you  say  about  economy  in  the  use  of 
steam? 

Ans.  This  is  an  element  of  vital  importance  and 
relates  to  the  distribution  of  the  steam  in  the 
cylinder.  It  embraces  the  least  amount  of  clearance 
or  dead  space  consistent  with  the  smooth  running 


70  ENGINEERS'  EXAMINATIONS. 

of  the  engine,  prevention  of  the  loss  of  heat  from  the 
steam  in  the  cylinder,  an  initial  steam  pressure  in  the 
cylinder  equal  to  the  boiler  pressure  ;  a  minimum 
back  pressure  ;  rapid  action  of  the  admitting  and 
cutting  off  edges  of  the  valve  ;  a  proper  amount  of 
cushioning  ;  and  last  but  not  least,  a  fitness  of  the 
engine  for  its  work,  in  size  and  the  character  of  the 
valve  gear. 

Qnes.     Is  regularity  of  speed  in  an  engine  of  importance? 

Ans.  One  of  the  most  essential  features  of  a 
good  engine  is  regularity  of  speed  under  varying 
loads.  A  high  attainment  in  this  respect  is  a  vari- 
ation of  only  3  per  cent,  in  two  revolutions. 

Ques.  What  have  you  to  say  about  the  fitness  of  an  en- 
gine for  its  proper  work? 

Ans.  It  is  of  the  utmost  importance  to  choose 
an  engine  of  the  proper  size  and  character  to  suit  the 
work  it  is  intended  for.  It  is  folly  to  purchase  a 
fixed  cut-off  engine  for  greatly  varying  loads  ;  it  is 
also  poor  economy  to  apply  to  a  small  steady  load  an 
expensive  automatic  cut-off  engine,  or  one  so  large 
that  the  ratio  of  expansion  becomes  excessive  and 
exceeds  the  limit  of  economy.  Each  steam  plant 
requires  its  special  engine  to  be  of  the  proper  pro- 
portion. 

(Jues.     What  is  ' '  clearance  "? 

Ans.  Clearance  in  a  cylinder  is  the  space  allowed 
for  the  piston  to  clear  the  cylinder  heads  at  the  end 
or  beginning  of  a  stroke. 


QUESTIONS  AND  ANSWERS.  ?1 

Clearance  is  also  a  term  used  to  include  also  the 
volume  of  the  ports.  It  is  evident  that  this  space, 
as  well  as  the  space  through  which  the  piston  sweeps, 
has  to  be  filled  with  steam. 

(Jucs.    What  is  "lead "? 

Ans.  Lead  is  the  amount  of  the  opening  of  the 
steam  port  at  the  beginning  of  the  stroke  of  the 
piston,  sometimes  called  pre-admission. 

Ques.    How  would  you  give  a  valve  its  lead? 

Ans.  Place  the  eccentric  sheave  ahead  of  its  true 
position. 

Ques.  To  cut  the  steam  off  at  a  given  part  of  the  stroke 
how  would  you  alter  the  valve? 

Ans.  By  making  the  width  of  the  face  of  the 
valve  larger  or  smaller,  as  the  case  demanded. 

Ques.    What  would  you  call  this  then? 
Ans.     Lap  or  cover. 

(Jues.    What  is  the  "  lap  "  of  a  valve? 

Ans.  The  "  lap  "  is  that  part  of  a  valve  which  is 
more  than  necessary  to  cover  the  steam  ports  when 
the  valve  is  in  mid-position. 

Ques.     Is  there  any  lap  on  the  exhaust  v^alve?    What  is  it? 

Ans.  There  is  exhaust  lap  and  it  is  how  much 
the  edge  of  the  exhaust  valve  is  over  on  the  cylinder 
bar  beyond  the  exhaust  edge  of  the  port  when  the 
valve  is  in  mid-position. 


ENGINEERS'  EXAMINATIONS. 


({lies.    Why  do  we  have  lap  on  the  exhaust  edge? 

Ans.     To  get  larger  cushion. 

(Jues.     What  kinds  of  engines  call  for  this? 

Ans.  Those  of  great  size  and  weight  having 
short  and  very  quick  travel 

Ques.     Why  is  "  lap  "  given  a  valve  at  all? 

Ans.  To  close  the  port  before  the  piston  reaches 
the  end  of  the  stroke,  and  thus  make  the  steam  work 
bv  its  expansion. 

Ques.  What  is  the  difference  between  fixed  and  movable 
expansion? 

Ans.  The  first  is  expansion  by  the  lap  of  the 
valve,  and  the  second  is  expansion  by  separate  gear- 
ing or  valves. 

(Jucs.  What  other  name  is  given  the  expansion  valve  for 
cut-off? 

Ans.     The  "  link." 

CJues.  Does  the  piston  stop  at  any  point  of  the  stroke? 

Ans.     Yes  ;  when  passing  the  centre. 

Qnes.  What  is  the  operation  of  the  slide  valve? 

Ans.  To  allow  the  steam  to  flow  alternately  first 
at  one  end  and  then  to  the  other  of  the  cylinder  and 
open  the  opposite  port  alternately  to  the  exhaust 

Ques.    What  is  the  object  of  a  crank? 

Ans.  To  convert  a  straight  line  motion  into  a 
circular  one. 


QUESTIONS  AND  ANSWERS. 


(Jues.  Describe  the  duties  of  a  slide  valve  with  reference 
to  the  positions  of  the  piston? 

Ans.  Steam  is  flowing  into  the  cylinder  and 
pushing  the  piston,  then  when  the  piston  has  trav- 
elled one-fourth  or  one-half  or  any  part  of  the  stroke 
before  determined  on,  the  valve  must  close  the 
steam  port  to  cause  expansion  ;  it  must  again  open 
this  port  to  the  exhaust  just  before  the  piston  arrives 
at  the  end  of  the  stroke  so  as  to  have  a  vacuum  to 
commence  the  return  stroke  with  ;  it  must  close  the 
exhaust  a  little  before  the  piston  arrives  at  the  other 
end  to  cause  cushioning  and  just  before  the  end  of 
the  stroke,  it  must  open  this  port  to  steam  to  com- 
mence the  new  stroke. 

(Joes.    What  do  we  mean  by  a  "  vacuum  "  ? 
Ans.     Any  space  void  of  all  pressure. 

(Jues.    Is  an  absolute  "vacuum  "  obtainable? 
Ans.     No. 

Ques.  Does  the  condenser  have  anything  near  a  perfect 
vacuum? 

Ans.  Yes,  quite  near  ;  but  there  is  always  a 
small  pressure  there. 

(Jues,     To  show  11  Ibs.  what  must  the  vacuum  gauge  read? 
Ans.     22  inches. 

(Jues.  What  does  11  Ibs.  vacuum  mean  to  a  steam  en- 
gineer? 


74  ENGINEERS1  EXAMINATIONS. 

Ans.  It  means  that  he  can  work  his  steam  down 
to  4  Ibs.  before  it  exhausts,  as  the  condenser  has 
destroyed  n  of  the  i5lbs.  atmospheric  pressure  at 
which  the  steam  would  usually  exhaust. 

(Jues.     What  is  implied  by  the  term  "back  pressure "  ? 

Ans.  As  perfect  vacuum  is  impossible,  a  certain 
vapor  retards  the  piston  equal  to  the  distance  be- 
tween a  perfect  vacuum  and  what  the  gauge  reads. 

Ques.  What  is  the  difference  between  a  high  and  low 
pressure  engine? 

Ans.  The  first  exhausts  into  the  air,  having  no 
condenser,  while  the  second  exhausts  into  a  con- 
denser, thus  saving  the  pressure  against  the  atmos- 
phere. 

Ques.    What  is  a  compound  engine? 

Ans.  An  engine  built  to  get  the  same  expansion 
not  of  the  steam  as  does  a  simple  engine,  but  by 
means  of  later  cut-off. 

({ncs.     How  do  they  contrive  to  do  this? 

Ans.  By  using,  in  addition  to  the  usual  high 
pressure  cylinder,  a  large  second  cylinder,  where  the 
steam  has  additional  room  for  expansion  before  es- 
caping into  the  condenser. 

(Jues.  Does  water  ever  get  into  the  cylinder,  and  what 
happens  when  it  does? 

Ans.  Sometimes  water  gets  in  through  priming 
and  is  apt  to  split  the  piston  or  blow  off  the  cover  of 
the  cylinder. 


QUESTIONS  AND  ANSWERS.  75 

Ques.    Can  you  get  rid  of  this  "water? 
Ans.     Yes,  by  the  escape  valves. 

Ques.  How  can  you  reverse  the  motion  of  a  slide  valve 
engine? 

Ans.  ist,  place  the  engine  on  the  dead  centre, 
noting  the  amount  of  lead  on  the  valve.  2d,  slack 
up  the  set  screw  of  the  eccentric  and  turn  it  ahead 
(same  way  it  has  been  running)  on  the  shaft  until 
the  valve  has  moved  to  the  extreme  of  its  travel.  3d, 
move  it  back  until  it  has  the  same  lead  as  before, 
and  tighten  the  set  screw. 

Ones.  In  putting  in  a  new  shaft,  how  would  you  adjust 
the  eccentric  ? 

Ans.  Put  the  crank  on  its  top  center  with  the 
valve  at  its  proper  lead  at  the  top.  Next  fasten  the 
sheave  with  set  bolts  to  keep  the  valve  lead  secure  ; 
when  all  is  connected,  then,  after  a  turn  of  the 
engine,  see  if  the  valve  has  the  proper  lead  at  the 
bottom  when  the  crank  is  on  the  bottom  centre.  If 
such  is  the  case,  mark  the  key  ways,  and  key  on  the 
sheave. 

Ques.    What  is  the  cylinder? 

Ans.  The  cylinder  consists  of  a  cast  iron  true 
bored  chamber  and  a  steam  chest  or  valve  box. 

Ques.  What  are  the  openings  from  the  steam  cheat  to  the 
cylinder  called? 

Ans.     Steam  ports. 


75  ENGINEERS'  EXAMINATIONS. 

Ques.    Which  are  the  exhaust  ports? 

Ans.  Those  which  open  from  the  cylinder  to  the 
air. 

Ques.    What  is  the  "stuffing-box  "  ? 

Ans.  The  "stuffing  box"  is  that  part  of  the 
cover  through  which  the  piston  passes.  It  is  ren- 
dered steam-tight  by  a  filling  or  packing  of  tallowed 
hemp,  etc. 

Ques.    What  is  the  « •  gland  "  ? 

Ans.  This  is  the  cover  which  presses  down  the 
packing  against  the  rod,  and  is  secured  by  two 
screwed  bolts. 

Ques.    What  is  cylinder  condensation? 

Ans.  It  is  that  portion  of  the  steam  which  con- 
denses and  is  deposited  on  the  metallic  surface  of 
the  cylinder  when  the  cylinder  is  colder  than  the 
steam  entering  it. 

Ques.     Does  this  moisture  remain  in  the  cylinder? 

Ans.  No.  It  evaporates  on  the  opening  of  the 
exhaust,  thereby  cooling  the  walls  of  the  cvlinder 
again. 

Ques.     What  is  the  result  of  all  this? 

Ans.  The  steam  is  lost  and  a  back  pressure  gen- 
erated thereby. 

Ques.    Is  this  loss  very  great? 


QUESTIONS  AND  ANSWERS.  77 

Ans.  Yes,  sometimes  being  as  much  as  50$  of 
the  whole  steam  consumed. 

Ques.     How  can  this  loss  be  partly  remedied  ? 

Ans.  i.  By  "jacketing"  the  cylinder  with  hot 
steam.  2.  By  ''cushioning"  or  detaining  and  com- 
pressing (thus  raising  the  temperature)  a  part  of 
the  exhaust  steam,  using  the  heat  thus  generated  to 
keep  the  cylinder  hot.  3.  Compounding  the 
cylinders. 

Ques.    How  would  you  test  for  a  leaky  slide  valve  ? 

Ans.  Block  the  fly-wheel  when  the  slide  valve  is 
in  the  middle  of  its  stroke  and  open  the  indicator 
taps,  or  the  relief  cocks,  or  look  at  the  exhaust  pipe. 
A  steady  escape  of  steam  indicates  a  leaky  valve. 

Ques.    How  would  you  test  for  a  leaky  piston  ? 

Ans.  Block  the  fly-wheel  when  the  piston  is 
situated  at  a  short  distance  beyond  the  beginning 
of  the  stroke.  Admit  steam  to  the  piston  and  open 
the  indicator  tap,  or  relief  cock,  on  the  exhaust  side 
of  the  piston.  An  escape  of  steam  will  indicate  a 
leaky  piston.  The  leak  may  be  caused  by  a  leaky 
slide  valve,  so  this  should  be  tested  fiist. 

Ques.  Should  engines  stand  idle  for  any  length  of  time, 
what  should  be  done  ? 

Ans.  They  should  be  turneu  partly  round  each 
day. 


78  ENGINEERS'  EXAMINATIONS. 

Ques.     What  should  be  done  before  starting  an  engine  ? 

Ans.  The  stop  valve  should  be  opened  a  little, 
before  the  fire  is  lighted,  so  that,  while  the  steam  is 
being  generated  in  the  boiler,  it  may  pass  through 
the  cylinders  and  jackets  and  warm  them  gradually, 
the  temperature  rising  as  the  pressure  rises.  Mean- 
while all  drain  cocks  from  the  slide  jackets  and 
cylinders  should  be  opened  to  allow  the  steam  to 
flow  through,  and  the  condensed  steam  to  pass 
away.  This  will  prevent  the  possibility  of  the 
cylinder  cracking  owing  to  sudden  admission  of  hot 
steam  against  the  cold  metallic  walls  of  the  cylinder. 
This  is  es'pecially  important  in  cold  weather. 

Ques.    How  would  you  manage  the  drain  cocks  ? 

Ans.  The  drain  cocks  should  remain  open  for  a 
few  revolutions  till  all  water  has  been  blown  out  of 
the  cylinder,  and  then  closed. 

Ques.    How  about  the  oil  ? 

Ans.  I  would  see  that  all  the  lubricators  were  in 
good  condition,  the  holes  clear,  and  the  worsteds 
clean,  and  that  the  lubricators  were  well  supplied 
with  oil. 

Ques.  If  a  low  pressure  or  condensing  engine,  how  would 
you  proceed  ? 

Ans.  If  a  condensing  engine,  the  vacuum  gauge 
should  be  watched  ;  and,  if  the  vacuum  is  not  main- 
tained, the  injection,  or  circulating  water,  should  be 


QUESTIONS  AND  ANSWERS.  79 

regulated.  If  this  does  not  produce  the  desired 
effect,  there  is  probably  an  air  leak  through  the 
piston-rod  gland,  or  the  air-pump-rod  gland,  which 
should  be  screwed  up  ;  and,  if  the  vacuum  is  still 
defective,  the  cause  must  be  looked  for  in  the  foot 
and  head  valves  or  the  air-pump  bucket  valve  (if  any)> 
or  in  leaky  condenser  tubes. 

Ques.  How  is  the  horse  power  of  steam  engines  deter- 
mined ? 

Ans.  By  the  following  rule  :  Multiply  the  area 
of  the  piston  in  square  inches  by  the  average  force 
of  the  steam  in  pounds  and  by  the  velocity  of  the 
piston  in  feet  per  minute  ;  divide  the  product  by 
33,000,  and  yV  of  the  quotient  equal  the  effective 
power. 

Ques.  How  is  the  "average  force"  of  the  steam  in  the 
cylinder,  or,  as  it  otherwise  is  expressed,  the  <4mean  effect- 
ive pressure  ",  found  ? 

Ans.  The  mean  effective  pressure  can  be  accu- 
rately determined  only  by  the  aid  of  an  indicator. 

Ques.  Without  the  aid  of  an  indicator  how  do  you  pro- 
ceed ? 

Ans.  When  the  indicator  is  not  used  in  the  cal- 
culation the  boiler  pressure  is  substituted  for  the 
mean  effective  pressure.  Deduct  from  the  result 
obtained  from  40  to  60  per  cent,  for  loss  by  conden- 
sation and  friction  of  steam  pipes  and  passages 


80  ENGINEERS'  EXAMINATIONS. 

decrease  of  pressure  in  cylinder  due  to  expansion, 
back  pressure  of  exhaust  and  friction  of  the  working 
parts.* 

Ques.     How  do  you  proceed  with  a  compound  engine  ? 

Ans.  By  the  same  rule  applied  to  each  cylinder — 
adding  the  totals  together  gives  the  power  of  the 
whole. 

Ques.    What  are  compound  engines  ? 

Ans.  Compound  engines  are  those  which  have 
two  or  more  cylinders  of  successively  increasing 
diameters  so  arranged  that  the  exhaust  steam  from 
the  first  and  smallest  cylinder  is  passed  forward  to 
do  work  in  a  second  cylinder  before  escaping  to  the 
condenser. 

Ques.  What  are  the  particular  advantages  claimed  by 
compounding  ? 

Ans.  i,  The  compound  engine  enables  the  full- 
est advantage  to  be  taken  of  the  expansive  power  of 
very  high-pressure  steam  ;  2,  The  ease  with  which  it 
may  be  adapted  to  work  on  one  or  more  cranks, 
thereby  reducing  the  excessive  variation  of  strain 
which  occurs  in  a  single  cylindered  engine  using 
high  pressure  steam. 

*NOTE.— The  mean  pressure  in  the  cylinder  when  cutting  off  at 

J4  stroke  equals  boiler  pressure  multiplied  by  .597 

X "   -670 

"  .743 
**  .847 
«  ,919 

"  .987 
"  .966 
-  .993 


QUESTIONS  AND  ANSWERS.  81 

Qnes.    How  may  compound  engines  be  classified '? 

Ans.  Into  those,  i,  where  the  piston  of  each 
cylinder  commences  the  stroke  at  the  same  time  ;  2, 
and  those  which  exhaust  from  one  cylinder  before 
the  next  cylinder  is  ready  to  receive  it ;  in  which 
case  the  steam  is  retained,  for  a  portion  of  the 
stroke,  in  a  chamber  or  receiver  between  the  two 
cylinders.  These  are  termed  " receiver"  engines. 

(Jues.  What  is  to  be  said  about  triple  and  quadruple 
expansion  engines  ? 

Ans.  The  principles  which  govern  the  construc- 
tion and  management  of  the  compound  are  the 
same  in  the  triple  and  quadruple  expansion  engines 
namely,' those  in  which  the  steam  is  expanded  in 
three  or  four  cylinders  respectively.  These  are  the 
necessary  outcome  of  increased  pressures  of  steam  ; 
for,  since  the  terminal  pressure  is  about  constant, 
increased  pressures  involve  an  increased  number  ol 
expansions.  And  in  order  to  prevent  undue  range 
of  stress  and  temperature,  three  and  even  four  cylin* 
ders  are  now  employed.* 


*  Thus  the  same  reasons  which  led  to  the  rejection  of  the  single- 
cylinder  engine  in  favor  of  the  two-cylinder  compound,  have  now  led 
to  the  rejection  of  the  two-cylinder  engine  (at  least,  in  marine  work), 
and  the  adoption  of  the  triple-compound,  and  in  some  cases  the 
quadruple  compound  in  its  stead.  The  steamer  "Northwest"— 
Buffalo  to  Duluth— has  engines  of  the  quadruple  cylinder  type  and 
are  worked  at  200  Ibs.  steam  pressure,  the  cylinders  being  25",  36",  51*^", 
74"  by  42"  piston  stroke,  120  revolutions,  developing  with  ease  7,000  H. 
P.  The  screws  (twin)  are  13  feet  diameter,  18  feet  pitch,  assuring 
speed  of  over  20  miles  Her  hour. 


82  ENGINE  AND  BOILER  FITITAGS. 


ENGINE  AND  BOILER  FITTINGS. 


In  the  efficient  operation  of  a  steam  plant,  next  to  a  well 
set  boiler  or  boilers  with  a  good  draught,  there  conies  an 
economical,  strong  and  suitably  proportioned  engine — one  or 
more. 

BUT,  not  less  an  importance  and  real  necessity  there  must 
be  the  connections,  fittings  and  appliances,  in  the  selection  of 
which  equal  care  and  good  judgment  must  be  brought  into 
play. 

In  the  choice  and  arrangement  of  these  fixtures  the  first 
thing  to  be  observed  is  that  they  .shall  be  of  the  very  best  of 
their  kind  as  far  as  may  be  possible.  2d,  each  appliance 
should  be  in  fair  proportion  to  the  other  parts  of  the  plant- 
neither  too  large  nor  too  small,  and  3d,  they  should  be  well 
and  thoroughly  ' '  fitted  " — the  skill  of  a  good  engineer  is 
shown  in  this  as  much  as  in  setting  a  main  valve  or  putting 
a  * '  spectacle  piece  "  on  a  boiler.  4th,  every  appliance  should 
be  kept  in  the  best  of  working  order  and  in  the  neatest  con- 
dition with  foresight  also  as  to  their  giving  away  at  an 
unexpected  moment. 

The  latter  consideration  implies  the  keeping  on  hand,  as 
far  as  practical,  of  duplicates  of  all  fittings  and  appliances, 
both  in  the  engine  and  boiler  rooms.  Especially  is  this  well 
where  "the  plant "  is  not  in  the  vicinity  of  shops  and  supply 
houses. 


QUESTIONS  AND  ANSWERS. 


Questions    and   Answers    relating   to    Engine 
and  Boiler  Fixtures. 

Ques.  What  are  the  principal  belongings  that  are  usually 
considered  fixtures  of  a  steam  boiler  ? 

Ans.  The  safety  valve  ;  globe  and  check  valves  ; 
steam  gauge;  the  front,  containing  tube,  fire  and 
ash  pit  doors  ;  grate  bars,  with  bearing  bars  ;  dead 
plates;  man  and  hand  hole  plates  and  thimbles; 
water  gauge  cocks  and  glass  gauges ;  blow-out 
apparatus  ;  fusible  plug  ;  surface  blow  cocks  with 
scum  apparatus  ;  steam  whistle  ;  and  for  the  brick 
work,  binder  bars,  anchor  bolts,  back  stays,  cleaning 
out  doors,  and  lugs  to  support  the  boiler. 

Ques.  What  other  appliances  can  you  name  necessary  to 
complete  the  operation  of  a  steam  boiler  ? 

Ans.  The  pump  or  injector ;  the  feed  water 
apparatus  with  piping  of  various  kinds  ;  the  steam 
pipe  (with  globe  valve)  leading  to  the  engine  ;  feed 
water  heater;  steam-trap;  the  chimney  and  damper; 
the  fire-tools,  flue  brushes  and  scaling  tools,  with  the 
hose  to  wash  out  the  boilers  ;  water  meters  ;  strain- 
ers and  foot-valves  for  clearing  the  water  before 
entering  the  boiler. 

Ques.    What  are  thimbles  in  use  on  boilers  ? 

Ans.  These  are  the  heavy  castings  riveted  on 
the  upper  shell  of  the  boiler  with  flanges  planed  to 
which  to  bolt  the  safety  valves  or  pipe  connections 
thimble  in  gas  pipe  definitions  is  "  a  connection." 


84  ENGINEERS'  EXAMINATIONS. 

Ques.    What  is  a  globe  valve  ? 

Ans.  A  globe  valve  takes  its  name  from  its  shape. 
It  is  a  valve  in  a  round  chamber. 

(Jues.     How  should  globe  valves  be  attached  ? 

Ans.  So  that  the  pressure  comes  under  the  valve, 
or  at  the  side,  for  if  the  valve  should  become  loose 
from  the  steam  (which  they  often  do)  if  the  pressure 
is  on  top,  there  would  be  a  total  stoppage  of  the 
steam. 

Ques.    What  is  a  valve  ? 

Ans.  A  valve  has  a  seat  and  is  generally  turneo 
by  a  circular  handle  fitted  to  the  spindle — the  best 
example  of  a  valve  is  that  of  an  ordinary  house 
pump,  where  the  valve  opens  upward  to  admit  the 
water  and  closes  downward  to  prevent  its  return. 

Ques.     What  is  a  cock  ? 

Ans.  A  cock  is  a  valve  but  a  valve  is  not  a  cock 
— the  cock  is  a  cone-shaped  valve  slotted  and  fitted 
with  a  handle — example  :  the  try-cocks  of  a  boiler 
are  cocks  with  their  openings  in  line  with  the  blow- 
off  pipes. 

Ques.    What  is  a  relief  valve  ? 

Ans.  It  is  a  valve  so  arranged  that  it  opens  out- 
ward when  a  dangerous  pressure  or  shock  occurs. 

Ques.    What  is  a  back  pressure  valve  ? 


QUESTIONS    AND    ANSWERS.  85 

Ans.  These  are  ball  (or  clack)  valves  in  a  pipe 
which  instantly  assume  the  seat  when  a  back  press- 
ure occurs.  Their  name  signifies  their  use — to 
maintain  a  constant  back  pressure  in  heating 
systems. 

Ques.    What  is  a  three-way  cock  ? 

Ans.  It  is  one  having  three  positions  in  which  to 
direct  the  fluid  in  three  ways.  There  is  also  a  three- 
way  valve. 

Ques.    What  is  a  check  valve  ? 

Ans.  A  valve  placed  between  the  feed  pipe  and 
the  boiler  to  prevent  the  return  of  the  water,  and 
similar  uses. 

Ques.    What  is  a  ball  valve  ? 

Ans.  It  is  a  valve  occupying  a  hollow  seat. 
These  valves  are  raised  by  the  passage  of  a  fluid  and 
closed  by  their  own  weight. 

Ques.    What  is  the  throttle  valve  ? 

Ans.  This  is  the  valve  used  to  admit  steam  to 
the  engine  and  so  used  (in  stationary  service)  to 
distinguish  it  from  the  main  stop  valve  located  near 
the  boiler — to  throttle  means  to  choke — hence  the 
throttling  of  the  steam. 

Ques.    What  is  a  reducing  valve  ? 

Ans.  This  is  a  pressure-regulating  valve  and 
designed  to  reduce  the.  pressure  from  a  high  point 


ENGINEERS1   EXAMINATIONS. 


in  the  boiler  to  a  low  one  in  a  system  of  steam  heat- 
ing. 

Ques.    How  should  steam  valves  be  connected  ? 

Ans.  So  that  the  valve  closes,  against  the  con- 
stant steam  pressure. 

Ques.  What  will  prevent  cracking  and  pounding  noises  in 
steam  pipes  in  steam  heating  ? 

Ans.     A  thorough  drainage  of  the  pipes. 

Ques.  In  steam  and  cast  iron  pipe  how  is  the  diameter 
given  in  the  tables  ? 

Ans.     By  the  internal  diameter. 

Ques.    And  the  diameter  of  boiler  tubes  ? 
Ans.     By  the  external  diameter 

Ques.  How  is  the  strength  of  steam  pipes,  elbows,  tees, 
threads,  etc.,  calculated  for  the  safe  working  pressure  ? 

Ans.  By  the  same  rules  that  are  used  in  figuring 
the  strength,  strains,  etc.,  of  the  steam  boiler. 

Ques.  What  factor  of  safety  would  be  best  in  view  of  the 
small  diameter  of  the  pipes  ? 

Ans.  A  tensile  strength  of  50,000  Ibs.  to  the 
square  inch  may  be  assumed  with  safety  with  a 
factor  of  4. 

Ques.    What  would  you  do  with  rusted  spots  ? 

Ans.  Regarding  rusted  spots  or  places  where 
corrosion  has  taken  place;  the  thickness  of  good 


QUESTIONS  AND  ANSWERS.  87 

iron  remaining  should  be  taken  as  the  thickness  of 
the  pipe  or  fitting,  although  small  places  having  an 
area  of  i  square  inch  or  less  may  be  ignored  so  long 
as  the  original  thickness  of  the  material  remains  ; 
but  where  the  corroded  area  exceeds  this,  full  allow- 
ancs  must  be  made.  A  number  of  small  places 
corroded,  pitted  or  grooved  and  closely  connected, 
require  that  only  the  thickness  of  good  iron  remain- 
ing shall  be  considered  as  the  thickness  of  the 
material. 

(jues.  What  is  the  tensile  strength  of  cast  and  malleable 
iron — of  which  connections  are  mostly  made  ? 

Ans.  The  mean  tensile  strength  of  cast  iron  is 
from  16,000  to  20,000  Ibs.  and  a  factor  of  safety  of  4 
should  be  employed.  The  mean  tensile  strength  of 
malleable  iron  ranges  from  30,000  to  40,000  Ibs.,  and 
unless  tests  are  made  to  determine  the  strength  it  is 
better  to  assume  the  smaller  number,  allowing  as 
before  a  factor  of  safety  of  4. 

(jues.    What  is  to  be  stated  about  the  pipe  tlireads  ? 

Ans.  The  threaded  portions  of  pipes  and  fittings, 
when  the  greater  portion  of  the  thread  is  entered 
and  the  joint  made  in  a  workman  like  manner,  will 
have  sufficient  strength  to  withstand  the  strain  on 
the  same  principle  that  the  single  riveted  girth 
seams  have  sufficient  strength  to  withstand  the 
strain,  even  though  the  longitudinal  seams  of  the 
boiler  be  double  riveted. 


88  ENGINEERS'  EXAMINATIONS. 

Ques.  In  taking  charge  of  a  new  steam  plant  what  is  the 
first  thing  an  engineer  should  do  ? 

Ans.  Make  himself  familiar  with  tne  water  and 
steam  pipes  and  office  of  the  valves  connected  with 
such  pipes. 

Ques.  What  are  the  dead  centres  or  dead  points  of  an 
engine  ? 

Ans.  At  two  instants  in  each  revolution,  the 
direction  of  the  crank  coincides  with  the  line  of 
connection  (or  straight  line  joining  the  centre  of  the 
joints  of  the  connecting  rods.)  The  positions  of  the 
crank  pins  at  those  instants  are  called  dead  points, 
and  they  correspond  to  the  ends  of  the  stroke  of  the 
pistons  when  its  velocity  vanishes. 

Ques.  What  means  are  provided  to  overcome  the  effects  of 
these  dead  points  without  jar  or  irregularity  ? 

Ans.  It  is  to  diminish  the  irregular  action  caused 
by  the  existence  of  these  dead  points  and  also  to 
facilitate  the  starting  of  engines  when  the  crank 
happens  to  rest  upon  one  of  them  that  engines  are 
combined  by  pairs  or  threes. 

Ques.  What  other  device  is  used  to  prevent  in  stationary 
engines  the  fluctuations  in  speed  caused  by  the  dead  centres  ? 

Ans.     The  fly  wheel. 

Ques.  Why  are  they  not  usecr  in  marine  and  locomotive 
engines? 

Ans.  In  marine  service  the  propeller,  whether 
paddle  or  screw,  answers  the  purpose  of  a  fly  wheel; 
in  locomotives  the  entire  engine  suffices  to  prevent 
excessive  fluctuations. 


QtTESTTONS  AbD  ANSWERS. 


Questions  and  Answers  Relating  to  the 
Safety  Yalve. 

(jnes.    What  is  a  safety  valve  ? 

Ans.  It  is  a  bonnet  or  conical  valve  loaded  witli 
a  weight  equal  to  the  greatest  extra  pressure  likely 
to  be  exerted  by  the  steam  on  the  boiler. 

Ques.    What  is  the  particular  office  of  the  safety  valve  ? 

Ans.  To  relieve  the  boiler  from  a  pressure  which 
may  become  dangerous  and  cause  an  explosion. 

Ques.  Is  the  sound  of  steam  from  a  safety  valve  a  sign  of 
danger  ? 

Ans.  No,  it  is  a  token  of  safety  ;  it  shows  the 
valve  to  be  in  operation,  and  if  properly  set,  a  sure 
protection. 

Ques.    What  danger  exists  when  a  safety  valve  "  sticks  "  ? 

Ans.  The  valve  holds  the  pressure  until  it  gets 
higher  and  higher,  until  so  very  high  that  the  safety 
valve  finally  gives  way  and  allows  so  much  steam  to 
escape  at  once  that  it  changes  the  condition  or 
balance  of  the  steam  and  water  inside  the  boiler, 
causing  danger  of  an  explosion. 

Ques.    How  should  this  be  guarded  against  ? 

Ans.  By  raising  the  valve,  when  under  pressure^ 
once  or  twice  a  day — doing  so  very  gently  and 
gradually — to  make  sure  that  it  is  in  working  order, 


90  EtfGINEEnS'  EXAMINATIONS. 

Ques.  When  a  safety  valve  is  described  as  a  2  inch  valve 
or  a  2i^  inch  valve,  what  is  indicated  by  the  description  1 

Ans.  It  means  that  2  inches,  or  2}'2  inches  is  the 
diameter  of  the  pipe. 

Ques.  What  part  of  the  boiler  is  preferable  for  the  position 
of  the  safety  valve  ? 

Ans.  It  is  best  placed  upon  the  boiler  at  the 
part  furthest  away  from  the  water  line,  so  as  to  be 
unaffected  by  the  foaming  of  the  water — if  any  exists, 

({ues.    Is  there  more  than  one  variety  of  the  safety  valve? 

Ans.  Yes.  The  Lever,  or  the  common  form,  and 
the  Spring  loaded  safety  valve ;  also  the  dead-weight 
safety  valve. 

Ques.    What  is  the  "pop "  safety  valve  ? 

Ans.  It  is  a  well-known  form  of  spring  valve 
and  takes  its  name  from  the  fact  that  it  takes  a  little 
more  pressure  to  raise  it  off  its  seat  than  what  it  is 
set  at,  consequently  it  releases  itself  with  a  "  pop  " 

Qnes.     What  are  the  points  of  contact  of  a  valve  called  ? 

Ans.  The  fixed  part  is  called  the  seat  of  the 
valve  and  the  part  resting  upon  it  is  called  the  face 
of  the  valve.  The  seat  is  preferably  adjusted  at  an 
angle  of  45  degrees  and  the  face  made  to  fit. 

Ques.    What  is  the  valve  spindle  ? 

Ans.  It  is  the  small  guiding  rod  which  moves 
upwards  and  downwards  with  the  face  of  the  valve. 
Its  office  is  to  keep  the  two  faces  opposite  and  cause 
the  rise  and  fall  to  be  perfectly  even  and  true. 


QUESTIONS   AND  ANSWERS.  91 

Ques.  What  are  the  irost  essential  problems  to  be  per- 
formed in  reference  to  the  steam  plant,  and  why  ? 

Ans.  Those  relating  to  the  safety  valve  ;  because 
the  safety  valve  is  the  most  important  fixture 
belonging  to  the  steam  boiler. 

(Jues.  Why  should  the  size  of  the  safety  valve  bear  a  cer- 
tain proportion  to  the  size  of  the  boiler  ? 

Ans.  Because  if  the  valve  is  too  large  it  is  liable 
to  be  blown  off  when  raised  by  excessive  pressure, 
and  if  too  small  then  it  will  not  relieve  the  boiler  in 
time  to  prevent  an  explosion 

Ques.     Can  you  give  the  rules  for  size  best  proportioned  ? 

Ans.  Rankine's  rule  for  the  dimensions  of  safety 
valves  is  :  Multiply  the  number  of  pounds  evaporated 
per  hour  by  .006  and  the  product  will  be  the  area  in 
square  inches  of  the  valve.  The  United  States 
steamboat  inspection  law  requires  for  the  common 
lever  valve  one  square  inch  of  area  of  valve  for  every 
two  square  feet  of  area  of  grate  surface.  A  rule 
adopted  by  the  Philadelphia  Department  of  Steam 
Engine  and  Boiler  Inspection  is  :  i.  Multiply  the 
area  of  grate  in  square  feet  by  the  number  22.5. 
2.  Add  the  number  8.62  to  the  pressure  allowed  per 
square  inch.  Divide  (i)  by  (2)  and  the  quotient 
will  be  the  area  of  the  valve  in  square  inches. 

Ques.  How  would  you  figure  for  36  feet  of  grate  surface 
with  80  Ibs.  pressure  ? 

Ans.  36  sq.  feet  of  grate  X  22.5  =  810.0.  Press- 
ure allowed  80  Ibs.  +  8.62  =  88.62;  810  -r-  88.62  = 
9.14  or  a  valve  having  a  diameter  of  3.4*. 


92  ENGINEERS'  EXAMINATIONS. 

Ques.  What  three  elements  enter  into  each  calculation 
relating  to  the  safety  valve  ? 

Ans.  i,  The  number  of  square  inches  on  the  face 
of  the  valve  and  the  pressure  of  the  steam  ;  2,  the 
weight  of  the  lever  and  valve  in  Ibs  ;  3,  the  amount 
of  the  weight  and  its  position  on  the  arm  of  the 
lever.* 

Qnes.  How  do  you  find  the  square  inches  of  a  valve,  the 
diameter  being  known  ? 

Ans.  By  multiplying  the  square  of  the  diameter 
of  the  circle  by  the  decimal  .7854. 

(Jues.  How  would  you  figure  the  pressure  on  a  3  inch 
valve  with  100  Ibs.  boiler  pressure  ? 

Ans.     Thus —  3  X  3  =  9  in. 

9  X  .7854  =  7.068  area. 
7.068  X  ioo  =  706.8  Ibs. 

Ques.     What  is  the  Lever  and  what  are  its  essential  points? 

Ans.  Of  the  six  mechanical  powers  (pully,  wheel, 
screw,  etc.)  the  lever  is  the  first  in  the  list. 

There  are  three  essentials  in  the  lever — i,  the 
fulcrum,  or  prop  ;  2,  the  power;  and  3,  the  weight; 
or,  differently  stated,  i,  the  point  on  which  the  bar, 
or  lever,  turns  (the  prop,  or  fulcrum);  2,  the  place 


*  The  weight  of  the  lever  and  valve  is  of  so  little  importance  in  the 
matter  of  pressure  that  examining  engineers  usually  omit  it  from  their 
questions. 


QUESTIONS    AND  ANSWERS. 


where  the  power  is  applied  ;  and  3,  the  point  where 
the  weight  is  applied.* 

Ques.    How  many  classes  or  kinds  of  levers  are  there  ? 

Ans.  There  are  three  classes  of  the  lever,  num- 
bered according  to  the  relative  position  ot  the 
fulcrum  ;  the  safety  valve  lever  is  a  lever  of  the  third 
kind. 

Ques.  "What  is  the  method  of  calculating  the  power  of  the 
lever  ? 

Ans.  The  same  calculation  applies  to  each  of 
the  three  classes  of  levers. 


Rule  for  Calculating  Levers. 

The  force  (P)  multiplied  by  its  distance  from  the 
fulcrum  (F)  is  equal  to  the  weight  (W)  multiplied 
by  its  distance  from  the  fulcrum. 

NOTE.— When  two  forces  act  upon  each  other  by  means  of  any 
machine,  that  which  gives  it  motion  is  called  THE  POWER,  and  that 
which  receives,  the  weight  (WEIGHT).  See  illustration. 

The  calculations  are  to  be  made  in  inches  for  distances  and  in 
pounds  for  the  forces  and  weights,  and  the  calculations  are  made  for 
the  action  of  mechanical  powers  upon  the  supposition  that  their  action 
is  not  affected  by  their  own  weight,  or  by  friction  and  resistance. 

*  In  the  safety  valve  lever  the  prop  or  fulcrum  is  the  hinge-joint 
upon  which  the  arm  moves,  the  point  where  the  power  is  applied  is  the 
conical  valve  being  pressed  upward  by  the  steam,  and  the  point  where 
the  weight  is  applied  is  on  the  arm  of  the  lever. 


ENGINEERS1  EXAMINATIONS. 


Ques.    What  rule  of  arithmetic  can  be  used  to  advantage 
in  working  safety  valve  problems  ? 

Ans.     The  rule  of  three  or  rule  of  proportion.* 


NOTE.— In  the  illustration  F  is  the  fulcrum ;  V  is  the  point  where 
the  pressure  is  exerted ;  W  is  the  weight ;  FV  is  6  inches  ;  and  VW  is 
10  inches ;  therefore  FW  is  16  inches. 

Ques.  When  the  length  of  the  lever,  the  weight  and 
length  of  the  short  arm  are  known,  give  the  rule  for  finding 
the  steam  pressure  the  weight  will  hold,  give  both  rule  and 
example. 

Ans.  RULE  (One). 

Multiply  the  length  of  the  lever  by  the  weight  and 
divide'  the  product  by  the  length  of  the  short  arm. 


*  This  "  rule  of  three  "  is  one  of  the  most  useful  in  the  whole  range 
of  mathematics ;  a  rule  by  which,  when  three  numbers  are  given,  a 
fourth  number  is  found. 


QUESTIONS    AND    ANSWERS.  95 

EXAMPLE. 

The  length  of  lever  being  20  inches,  the  weight  20 
Ibs.  on  the  end  of  it,  and  the  short  arm  being  4 
inches,  then 

The  length  of  the  lever,  20 

Multiplied  by  the  weight,          20 

Divided  by  the  short  arm,  4)400 

Answer,  100  Ibs.  resistance.* 

Ques.  When  the  diameter  of  the  valve,  the  steam  press- 
ure, the  length  of  the  short  arm  and  the  weight  are  known, 
what  is  the  rule  to  find  the  place  to  hang  the  weight  ?  Give 
rule  and  example. 

Ans.  RULE  (Two). 

Multiply  the  steam  pressure  in  Ibs.  by  the  length 
of  the  short  arm  of  the  lever  in  inches,  and  divide 
the  product  by  the  weight  of  the  ball. 

EXAMPLE. 

The  diameter  of  the  valve  being  2^  with  steam 
at  60  Ibs.  gives  the  resistance  to  be  overcome  (/.  e., 
2.5  X  2.5  X. 7854  =  41?  area  of  valve  multiplied  by  60 
Ibs  )  294  Ibs.;  the  short  arm  of  the  lever,  3  inches; 
weight  of  ball,  40  Ibs.     Now  then  : 
The  resistance  (steam  pressure)  =  294 
The  short  arm,  3 

Divide  by  weight,  40)882 

22.05  inches  of  lever. 

*  This  100  would  represent  a  valve  area  of  3J^  sq.  in.  at  40  Ibs.  press- 
ure, etc 


96  ENGINEERS1  EXAMINATIONS. 

(Jues.  When  the  steam  pressure,  the  short  arm,  and  the 
length  of  the  lever  are  known,  to  find  weight  of  ball  needed. 
Give  rule  and  example. 

Ans.  RULE  (Three). 

Multiply  the  steam  pressure  by  the  short  arm.  and 
divide  the  product  by  the  length  of  the  lever,  the 
answer  is  the  weight  of  the  ball. 

EXAMPLE. 

The  steam  pressure  (as  in  the  last  example)  being 
294,  the  short  arm  2  inches,  and  the  length  of  the 
lever  30  inches.  Now  then  : 

The  steam  pressure,  294 

Multiplied  by  the  short  arm,       2 

Divided  by  the  lever,  30,588 

Weight  of  ball  needed,  19.6     Ibs. 

Ones.  When  the  weight,  length  of  lever  and  the  steam 
pressure  (resistance)  are  known,  to  find  the  length  of  the 
short  arm.  Give  rule  and  example. 

Ans.  RULE  (Four). 

Multiply  the  length  of  the  lever  by  the  weight  and 
divide  the  product  by  the  steam  pressure. 

EXAMPLE. 

The  lever  being  20  in.,  weight  20  Ibs.,  steam  press- 
ure 100  Ibs.  Now  then  : 

Length  of  lever,  20 

Weight,  20 

Divide  by  steam  pressure,  100)400 
Length  of  short  arm,  4  inches.* 

*  This  100  represents  the  total  steam  pressure  on  the  valve— the 
example  given  being  the  reverse  of  the  one  for  rule  one. 


QUESTIONS  AND  ANSWERS.  97 

Ques.  If  the  ball  is  removed  from  the  lever  can  there  be 
any  steam  pressure  on  the  boiler  ? 

Ans.  Yes  ;  that  due  to  the  weight  of  the  valve 
and  stem.  If  they  weigh,  say  2  Ibs.,  and  the  area  of 
the  valve  is  7  sq.  inches,  then  that  would  cause  a 
pressure  of  f  of  one  Ib.  before  the  steam  blows  off. 

Ques.    What  about  the  lever  itself  ? 

Ans.  The  weight  of  the  lever  also  operates  the 
same  way,  except  it  is  not  a  dead  weight. 

Ques.     Explain  why  it  is  not  a  dead  weight. 

Ans.  If  you  have  a  lever  30  inches  long  and  it 
has  the  same  size  from  end  to  end,  its  balancing 
center  will  be  in  the  middle,  or  15  inches.  If  the 
lever  (bar)  weighs  8  Ibs.  it  will  have  the  effect  of 
hanging  a  ball  of  8  Ibs.,  15  inches  from  the  fulcrum. 

Ques.  Is  there  anything  else  which  should  be  thought  of 
in  figuring  the  safety  valve  problems  ? 

Ans.  Yes,  a  possible  difference  in  the  true 
diameter  of  the  valve  or  connection  pipes — the 
opening  of  the  valve  may  be  2  inches  diameter,  but 
the  circle  of  contact  of  face  and  seat  may  be  2^ — 
this  would  make  a  difference  of  nearly  %  sq  inch  of 
area.* 

*  This  difference  need  not  be  considered  important  in  view  of  the 
factor  of  safety  (6)  usually  allowed,  i.  e.,  the  boiler  is  made  to  with- 
stand  six  times  the  ordinary  pressure :  BUT,  it  bears  upon  the  question 
of  omitting  the  weight  of  valve  spindle  and  lever  from  common  calcu- 
lations. 


ENGINEERS'  EXAMINATIONS. 


TABLE  OF  PROPERTIES  OF  SATURATED  STEAM. 


Absolute 
pressure 
in  Ibs.  per 
sq.  in. 

Tempera- 
ture Fan. 

Total  heat  of 
evaporation 
from  water  at 
32°  F. 

Volume 
per  Ib.  in 
cubic  feet. 

1 

102.0 

1113.0 

330.36 

2 

126.4 

1120.5 

172.08 

3 

141.6 

1125.1 

117.52 

4 

153.1 

1128.6 

89.62 

5 

162.3 

1131.4 

72.66 

6 

170.1 

1133.8 

6121 

7 

176.9 

1135.9 

5294 

8 

183.0 

1137.7 

46.70 

9 

188.4 

1139.4 

41.80 

10 

193.3 

1140.9 

37.84 

11 

197.8 

1142.3 

34.63 

12 

202.0 

1143.5 

31.90 

13 

205.9 

1144.7 

29.57 

14.7 

212.0 

1146.6 

26.36 

15 

213.1 

1146.9 

25.85 

16 

216.3 

1147.9 

2432 

17 

219.5 

1148.9 

22.96 

18 

222.5 

1149.8 

21.78 

19 

225.3 

1150.6 

20.70 

20 

228.0 

1151.5 

19.72 

21 

230.7 

1152.3 

18.84 

22 

233.3 

1153.1 

18.03 

23 

235.8 

1153.9 

17,26 

24 

238.2 

1154.6 

16.64 

25 

240.5 

1155.3 

16.00 

26 

242.7 

1156.0 

15.38 

27 

2448 

1156.6 

14.86 

28 

246.8 

1157.2 

1437 

29 

248.7 

1157.8 

13.90 

80 

250.5 

1158.3 

13.46 

QUESTIONS  AND  ANSWERS. 


TABLE  OF  PROPERTIES  OF  SATURATED  STEAM. — Continued.* 


Absolute 
pressure 
in  Ibs.  per 
sq.  in. 

Tempera- 
ture Fah. 

Total  heat  of 
evaporation 
from  water  at 
32°  F. 

Volume 
per  Ib.  in 
cubic  feet. 

35 

259.3 

1161.0 

11.65 

40 

267.0 

1163.4 

10.28 

45 

274.4 

1165.6 

9.18 

50 

281.0 

1167.6 

861 

55 

287.1 

1170.0 

7.61 

60 

292.6 

1171.2 

7.01 

.  65 

298.0 

1172.7 

6.49 

70 

302.8 

1174.3 

6.07 

75 

307.5 

1175.7 

5.68 

80 

312.1 

1177.1 

5.35 

85 

316.1 

1178.4 

5.05 

90 

320  3 

•1179.6 

4.79 

95 

324.1 

1180.8 

4.55 

100 

327.7 

1181.9 

4.33 

105 

331.3 

1182.4 

4.14 

110 

334.6 

1184.0 

3.97 

115 

338.0 

1184.5 

3.80 

120 

341.1 

1186.9 

3.65 

130 

347.2 

1187.9 

3.38 

140 

352.9 

1189.6 

3.16 

150 

358.3 

1191.2 

2.96 

160 

363.4 

1192.8 

2.79 

170 

368.3 

1194.3 

2.63 

180 

383.0 

1195.7 

2.49 

190 

377.5 

1197.1 

2.37 

200 

381.8 

1198.4 

2.26 

250 

400.8 

1204.2 

1.83 

300 

417.1 

1209.2 

1.54 

350 

430.1 

1212.2 

1.33 

400 

445.0 

1217.7 

1.18 

*  Regnault. 


100  SATURATED  STEAM. 


SATURATED  STEAM. 


This  has  been  defined  on  page  59  as  the  steam  which  rests 
upon  the  water  within  a  boiler  under  pressure.  Attention  is 
now  invited  to  the  Tables  (Regnault's)  on  the  two  preceding 
pages. 

Let  water  at  32°  be  heated  in  a  closed  vessel,  such  as  an 
ordinary  steam  boiler,  containing  space  for  the  accumulation 
of  steam,  and  let  heat  be  gradually  applied.  Then  the  tem- 
perature of  the  water  will  gradually  rise,  and  steam  will  be 
formed. 

As  the  heat  is  increased,  the  temperature,  pressure,  and 
density,  or  weight  per  cubic  foot,  of  the  steam  increase 
indefinitely,  so  long  as  the  strength  of  the  boiler  is  not 
exceeded  ;  and  the  relation  between  the  temperature,  press- 
ure, and  density  always  bears  a  certain  fixed  relation. 

If  heat  is  applied  so  as  to  maintain  the  temperature  con- 
stact,  the  pressure  and  density  remain  constant  also,  and 
evaporation  ceases.  If  a  communication  be  opened  between 
the  boiler  and  engine,  on  escape  of  steam  from  the  boiler  the 
pressure  is  momentarily  reduced  and  re  evaporation  com- 
mences rapidly.  So  long  as  the  temperature  is  maintained, 
no  sensible  variation  of  pressure  is  noticeable  in  a  boiler  sup- 
plying steam  to  an  engine. 


SATURATED -srSA'te.- 


idf 


It  will  be  observed  from  the  tables  that  saturated  steam 
under  a  given  pressure  has  a  fixed  temperature,  also  that  the 
temperature  and  density  increase  with  the  pressure. 

But  it  will  be  further  noticed  that  the  total  heat  increases 
in  a  very  slow  ratio  compared  with  the  pressure  and  temper- 
ature, there  being  only  a  very  small  increase  of  total  heat 
per  Ib.  of  steam  as  the  pressure  increases.  This  is  an 
important  point  in  practice  when  considered  in  reference  to 
coal  consumption,  for  it  shows  that  it  is  not  much  more 
costly  in  fuel  to  generate  high-pressure  steam  than  low- 
pressure  steam,  weight  for  weight  ;  and  that  far  more  work 
can  be  obtained  from  it  when  used  expansively  than  from 
the  same  weight  of  low-pressure  steam — hence  the  economy 
of  high-pressure  steam. 

In  this  connection  it  is  interesting  and  important  to  com- 
pare the  difference  in  the  weight  of  water  required  to  cool  a 
given  weight  of  water,  with  that  required  to  cool  the  same 
weight  of  steam  at  the  same  temperature. 

This  is  owing  to  the  mysterious  element  which  exists  in 
steam  under  pressure — very  like  the  unknown  essential  prop- 
erty of  electricity — called  latent  heat.  In  generating  water 
into  steam  there  is  absorbed  about  five  and  one -half  times  as 
much  heat  as  is  required  under  atmospheric  pressure,  to 
raise  the  temperature  of  the  water  from  freezing  point,  32° 
F.,  to  boiling  point,  212°  F.,  an  amount  of  heat  which 
if  the  water  were  a  fixed  solid  would,  it  is  said,  render  it  red 
hot  by  daylight.  Tested  by  a  thermometer  the  steam  will 
show  only  212°,  but  by  experiment  1000°,  nearly,  have  been 


102 


SATURATED  STEAM. 


added,   which   is  stored  up  in  some  hidden  unaccountable 
way  ;  this  is  called  the  latent  heat  of  steam. 

There  are  two  sorts  or  conditions  of  heat  in  the  process  of 
iL.team  production  operating  upon  water  :  1,  Sensible  heat;  2, 
Latent  or  insensible  heat  ;  hence  the  constituent  or  total 
heat  of  steam  consists  of  its  latent  heat  in  addition  to  its 
sensible  heat. 

The  appropriation  of  the  heat  expended  in  the  generation 
of  one  pound  of  saturated  steam  at  212°  F. ,  from  water  sup- 
plied at  32°  F.,  may  be  exhibited  thus  :— 

To  GENERATE  ONE  POUND  OF  STEAM  AT  212°  F. 


Units  of  heat. 


The  sensible  heat : — 

1.  To  raise  the  tempera- 

ture of  the  water 
from  32°  to  212°  F., 

The  latent  heat  :— 

2.  In    the    formation    of 

steam 892.935 

3.  In  resisting  the  incum- 

ben  t  atrno  spheric 
pressure  of  14.7  Ibs. 
per  square  inch,  or 
2116.4  Ibs.  per  square 
foot.,  72.265 


180.9 


Total  or  constituent  heat. . . 


965.2 
1146.1 


Mechanical  equiva- 
lent in  foot-pounds. 


139,655 


689,346 


55,788 


745,134 

884.789 


Ques.    What  is  the  rule  for  finding  the  total  heat  in  steam? 

Ans.     Multiply  temperature  or  sensible   heat  of 
the  steam  by  .3  (TV)  and  add  it  to  1115°. 


SATURATED  STEAM.  103 

.(Jues.  Give  an  example.  What  is  the  total  and  latent 
heat  in  steam  that  is  100  Ibs.  by  the  gauge  ? 

Ans.  ioo  Ibs.  by  the  gauge  is  115  gross,  the  15 
being,  approximately,  the  weight  of  the  atmosphere, 
and  115  gross  has  (by  Table  page  99)  338°  of  heat, 
hence, 

338  X  .3  =  101.4  +  1115°  =  1216.4  =  total  heat. 

338.0  =  sensible  heat 

8781%  latent  heat.* 

(Jues.    What  are  the  total  units  of  heat  in  steam  of  212°  ? 
Ans.     2i2°x. 3  =  63.6+1115°  =  1178.6°  total  heat. 

(Jues.    What  is  the  latent  heat  in  this  case  ? 
Ans.     1178.6  =  total  heat. 

212     =  sensible  heat. 

966.6  =  latent  heat. 

Ques.  If  the  temperature  of  the  feed  water  is  known,  what 
will  be  the  number  of  units  of  heat  to  each  Ib.  of  water 
turned  into  steam  ?  Give  illustration. 

Ques.  If  the  steam  in  the  boiler  be  270°  and  the  feed  water 
be  at  110°  how  many  units  of  heat  will  it  be  necessary  to  add 
to  this  water  to  turn  a  Ib.  of  it  into  steam  ? 

Ans.  270  X  .3  =  81  -f- 1115  =  1196,  less  feed  water 
no=  1086. 

*  The  small  variation  between  the  results  in  the  examples  and  the 
figures  in  the  Table  is  caused  by  greater  detail  of  calculation  in  one 
more  than  the  other.  In  the  examples  the  air  pressure  is  extended  at 
15  ibs.  per  square  inch  and  in  the  Tables  at  147. 

Let  it  be  remembered  that  a  Thermal  unit  (expressed  by  T.  U.)  is 
the  raising  of  1  Ib.  of  water  1  degree,  and  that  the  mechanical  force 
updating  in  each,  unit  is  772  Ibp, 


104  ENGINEER'S  EXAMINATIONS. 

Ques.  Which  conducts  heat  best,  dry  steam  or  cloudy 
steam  ? 

Ans.  Dry  steam  is  a  poor  conductor  of  heat  as 
compared  with  either  liquid  water  or  cloudy  steam, 
for  after  cloudy  steam  has  received  heat  enough  to 
make  it  dry  or  nearly  dry  it  receives  additional  heat 
very  slowly. 

Ques.  If  a  steam  jacket  is  used,  is  the  steam  hi  the  cylin- 
der affected  by  the  heat  of  the  steam  in  the  jacket  ? 

Ans.  It  is  assumed  that  the  steam  in  the  cylinder 
while  expanding,  receives  just  enough  of  heat  from 
the  steam  in  the  jacket  to  prevent  any  appreciable 
part  of  it  from  condensing  without  superheating  the 
steam  in  the  cylinder. 

Ques.  Is  there  any  gam  hi  using  steam  at  100  Ibs.  and  by 
expansion  making  the  mean  effective  pressure  70  Ibs.  over, 
using  steam  of  70  Ibs.  throughout  the  entire  stroke  ? 

Ans.  Using  a  cylinder  with  a  volume  of  i  cubic 
foot,  and  an  initial  pressure  of  70  Ibs.  continued 
throughout  the  stroke,  would  be  using,  at  each  stroke, 
a  cubic  foot  of  70  Ib.  steam,  or  a  weight  of  .201  of  a 
pound.  Now,  should  the  initial  pressure  be  100  Ibs., 
a  cut-off  at  fa  stroke  would  give  the  desired  mean 
effective  pressure  of  70  Ibs.  and  only  use  fa  cubic 
feet  of  steam.  Now,  100  Ibs.  steam  weighs  .264  Ib. 
per  cubic  foot ;  fa  cu.  ft.  therefore  =  .099,  so  that 
only  .099  Ib.  would  be  used  against  .201  Ib.  of  the 
lever  pressure  steam,  as  in  the  first  case.  Thus  by 
working  steam  expansively  you  have  a  gain  of 
.201  — .099  =  .102  Ib.  at  each  l/2  stroke. 


PUMPS.  106 


PUMPS. 


Upon  the  uniform  operation  of  the  pump  depends  the 
safety  and  comfort  of  the  engineer,  owner  and  employees, 
and  indirectly  of  the  success  of  the  business  with  which  ' '  the 
plant "  is  connected. 

Pumps  now  raise,  convey  and  deliver  water,  beer,  molasses, 
acids,  oils,  and  melted  lead.  They  also  handle  such  gases  as 
air,  ammonia,  lighting  gas  and  even  oxygen. 

Pumps  are  made  in  various  forms  and  sizes  ;  they  vary  in 
design  to  suit  their  several  uses,  and  are  defined  as  rope, 
chain,  diaphram,  jet,  centrifugal,  rotary,  oscillating,  cylin- 
der. 

It  is  with  the  last  named  class  with  which  the  engineer 
has  principally  to  become  expert.  Cylinder  pumps  are  of 
two  kinds,  single  acting  and  double  acting. 

The  feed  pump  is  used  to  supply  the  boiler,  and  it  is 
required  to  supply  a  quantity  of  water  at  least  equal  to  that 
evaporated  and  passed  forward  to  the  engine,  together  with 
leakage  at  safety  valve,  &c. ;  and  to  provide  also  for  emer- 
gencies it  is  usually  made  capable  of  supplying  from  2 
times  this  quantity. 


106 


PUMPS. 


The  action  of  the  pump  may  be  explained  as  follows :  Sup- 
pose the  plunger  P  at  the  bottom  of  its  stroke,  and  the  whole 
interior  of  the  pump  to  be  full  of  air.     When  the  plunger 
rises  the  pressure  of  the  suction  valve  S  will  be  reduced,  and 
the  air  in  the  supply  pipe  will  lift  the  valve  and  flow  into  the 
barrel.     The  pressure  of  the  air  in  the  supply  pipe  is  now  less 
than  before,  and  accordingly  the  pressure  on  the  external 
surface  of  the  wa- 
ter forces  water  up 
the  pipe  to  such  a 
height  as  to  make 
the  pressure  inside 
the  pipe  balance  the 
pressure     outside. 
When  the  plunger 
returns  the  suction 
valve  is  closed  by 
the   pressure,   and 
the  air  is  forced  out 
through  the  deliv- 
ery valve  D.     Each 
time  the  stroke  of 
the  plunger  is  re-  THE  PUMP. 

peated,   the  water 
will  rise  in  the  sup- 
ply pipe  until  at  last  it  reaches  and  fills  the  barrel.     Now, 
when  the  plunger  returns,  it   forces   water  instead   of  air 
through  the  delivery  valve. 

The  height  of  the  column  of  water  which  will  balance  the 
pressure  of  the  atmosphere  is  34  ft. ;  that  is,  a  column  whose 


PUMPS.  107 

weight  is  about  15  pounds  per  sq.  in.  In  practice,  however, 
the  supply  can  never  be  drawn  from  a  depth  greater  than 
about  25  ft. 

The  valves  are  prevented  irom  rising  above  a  certain  height 
by  stops  shown  in  the  figure.  The  lift  of  a  valve  should  not 
exceed  one -fourth  of  its  diameter,  for  with  this  lift  the  whole 
of  the  water  which  passes  through  the  valve  seating  can 
escape  freely  round  the  edge  of  the  valve.  Any  further  lift 
is  therefore  unnecessary. 

Air  vessels  A,  V,  are  chambers  fitted  to  pumps  close  to  and 
beyond  the  delivery  valve.  The  air  in  the  water  collects  in 
this  vessel  and  forms  a  cushion  or  spring  which  enables  the 
water  to  be  delivered  in  a  steady  stream. 

(Jues.    What  is  a  single  acting  pump  ? 

Ans.  A  single  acting  pump  does  its  work  through 
one  end  of  the  cylinder. 

Ques.    What  is  a  double  acting  pump  ? 

Ans.  It  is  an  engine  and  pump  combined  ;  in 
double  acting  pumps  the  motion  of  the  piston  in  one 
direction  causes  an  inflow  of  water,  and  a  discharge 
at  the  same  time,  in  the  other  ;  and  on  the  return 
stroke  the  action  is  renewed  as  the  discharge  end 
becomes  the  suction  end.  The  pump  is  thus  double 
acting. 

Ques.    In  a  steam-pump  what  are  the  two  ends  called  ? 

Ans.  The  steam-end,  which  is  a  complete  steam 
engine,  and  the  water-end,  into  which  the  water  is 
drawn,  and  from  which  it  is  discharged. 


108  ENGINEERS'  EXAMINATIONS. 

Ques.    What  is  the  connection  between  these  ends  —  if  any  ? 

Ans.  The  water  and  steam  ends  are  operated  by 
a  single  rod,  called  the  piston  rod,  which  extends 
through  from  one  end  to  the  other  —  a  pump  so 
operated  is  a  direct  acting  steam  pump. 


What  is  the  force   against  which  a  pump  works 
aside  from  the  boiler  pressure  ? 

Ans.  Gravity,  or  the  attraction  of  the  earth, 
which  prevents  the  water  from  being  lifted.  This  is 
shown  in  the  fact  that  water  can  be  led,  or  trailed 
an  immense  distance,  limited  only  by  the  friction, 
by  a  pump* 

Ques.  What  is  the  difference  between  a  suction  and  a 
discharge  valve  ? 

Ans.  The  suction  valve  prevents  the  return  of 
the  water  after  it  has  entered  the  cylinder,  and  the 
discharge  valve  permits  the  outward  passage  of  the 
water  but  does  not  allow  its  return. 

Ques.    Is  it  true  that  water  is  raised  by  suction  ? 

Ans.  No.  Water  is  raised  by  pressure  of  air  on 
the  water  outside  the  pump.  The  piston  of  the 
pump  exhausts  the  air  and  the  unbalanced  weight  of 
water  causes  it  to  rise  within  the  pump  or  pipes 
supplying  the  pump. 

(Jues.    What  is  the  limit  of  this  lift  ? 

Ans.  About  33  feet,  because  water  of  one  inch 
area  weighs  14117  Ibs.,  which  is  the  weight  of  one 


QUESTIONS  AND  ANSWERS.  109 

inch  of  air,  at  the  sea  level.  Pumps  must  be  in 
good  order  to  lift  33  feet,  and  all  pipes  and  valves 
must  be  perfectly  air  tight ;  pumps  will  give  better 
satisfaction  lifting  from  22  to  25  feet. 

Ques.  In  designing  or  purchasing  pumps  what  is  the  safe 
rule  as  to  capacity  ? 

Ans.  One  should  be  selected  capable  of  deliver- 
ing one  cubic  foot  of  water  per  horse  power  per 
hour  ;  or  say,  three  pounds  of  water  for  each  square 
foot  of  heating  surface. 

Ques.    Why  will  not  a  pump  lift  hot  water  ? 

Ans.  Because  the  vapor  from  the  hot  water  fills 
the  vacuum  as  fast  as  it  is  made  by  the  piston  and 
destroys  its  force,  hence,  no  pump,  however  good, 
will  lift  hot  water. 

Qnes.  What  is  the  best  method  of  getting  around  this 
difficulty  ? 

Ans.  The  pump  should  be  placed  below  the 
supply,  so  that  the  water  may  flow  into  the  valve 
chamber. 

Ques.  What  is  the  most  necessary  condition  for  the  satis- 
factory operation  of  a  pump  ? 

Ans.  A  full  and  steady  supply  of  water.  The 
pipe  connections  should  in  no  case  be  smaller  than 
the  openings  in  the  pump,  and  the  suction  lift  and 
delivery  pipes  should  be  as  straight  and  smooth  on 
the  inside  as  possible. 


110  ENGINEERS'  EXAMINATIONS. 

Ques.    What  is  the  advantage  of  the  suction  chamber  ? 

Ans.  It  prevents  pounding — makes  the  action  of 
the  pump  easy  and  uniform  and  enables  the  pump 
barrel  to  fill  when  the  speed  is  high. 

(Jues.    How  should  pumps  be  left  in  cold  weather  ? 

Ans.  Pumps  should  always  be  drained  in  cold 
weather,  as  freezing  of  water  in  pipes  or  cylinders  is 
sure  to  burst  them.  Engineers  should  therefore  be 
careful,  and  open  the  drip  plugs  or  cocks,  which  are 
provided  on  all  pumps  for  draining  them. 

Ques.  What  directions  would  you  give  as  to  setting  up  a 
pump? 

Ans.  Use  as  few  bends  and  valves  as  possible, 
and  run  every  pipe  in  as  direct  line  as  practicable, 
and  where  convenient  use  full  round  bends  rather 
than  elbows,  for  valves,  returns  and  elbows  increase 
friction  more  rapidly  than  length  of  pipe  ;  never  use 
pipes  too  small  in  diameter;  in  long  pipes  this 
should  be  increased  to  allow  for  increased  friction, 
especially  in  suction  pipes. 

Qnes.  In  ordering  a  pump  what  is  it  for  the  interest  of  the 
purchaser  for  the  builder  to  know  ? 

Ans.  i st.  For  what  purpose  is  the  pump  to  be 
used,  and  the  average  pressure  of  steam  ? 

2d.  What  is  the  liquid  to  be  pumped,  and  is  it  hot 
or  cold,  clear  or  gritty,  fresh,  salt  or  acidulous? 

3d.  What  is  the  maximum  quantity  to  be  pumped 
per  hour  ? 


QUESTIONS  AND  ANSWERS.  HI 

4th.  To  what  height  is  the  liquid  to  be  lifted  by 
suction,  also  the  height  of  discharge  ?  What  are  the 
length  and  diameter  of  the  suction  and  discharge 
pipes,  and  the  number  of  elbows  or  turns? 

Qucs.  Granted  motion  to  the  piston  or  plunger  of  a  pump 
what  is  the  only  cause  that  makes  it  fail  with  an  abundance 
of  water  ? 

Ans.  A  pump  fails  because  it  leaks — there  can 
be  no  other  reason,  and  the  leak  should  be  found 
and  repaired.  Leaky  valves  are  common  and  should 
be  ground  ;  leaky  plungers  are  frequent  and  should 
be  re-turned  in  a  lathe  ;  leaky  pistons  sometimes 
exist  and  they  should  be  repaired.  The  rod  must  be 
straight  as  far  in  as  the  packing  and  that  must  be 
kept  free  from  dirt  and  sediment. 

Ques.    What  should  long  suction  pipes  be  provided  with  ? 

Ans.  A  foot  valve,  just  above  the  strainer,  in  the 
well  or  pit. 

Ques.    What  are  direct  acting  steam  pumps  ? 

Ans.  These  have  a  single  cylinder  non-expanding 
and  in  larger  sizes  with  double  cylinders  on  the 
compound  principle.  These  pumps  may  be  divided 
into  two  classes  ;  those  having  the  valve  gear  on  the 
outside  where  it  can  be  seen,  and  those  having  the 
valve  gear  inside,  no  moving  parts  being  visible 
when  the  pump  is  in  operation  except  the  piston 
rod. 

Ques.     What  are  direct  acting  duplex  pumps  ? 


112  ENGINEERS1  EXAMINATIONS. 

Ans.  These  are  two  steam  pumps  placed  side  by 
side,  so  combined  that  the  slide  valve  of  each 
cylinder  gets  its  motion  from  the  opposite  piston 
rod  through  a  lever  and  rockshaft.  The  single 
direct  acting  and  the  duplex  direct  acting  pumps 
are  almost  always  double  acting  pumps,  having  the 
steam  piston  and  the  water  piston  at  the  two  ends 
of  the  same  rod.  Therefore  the  steam  pressure 
exerted  upon  the  steam  piston  will  be  exerted  upon 
the  water  piston  direct. 

(Jues.     What  are  pumping  engines  ? 

Ans.  It  has  become  customary  to  apply  the  term 
pumping  engines  to  large  reciprocating  pumps  used 
for  supplying  cities  and  towns  with  water,  draining 
lakes  and  marshes,  and  other  purposes,  although 
strictly  speaking  any  steam  pump  with  its  motor 
arranged  in  one  machine  is  a  pumping  engine. 

Ques.  Which  should  have  the  larger  area,  the  steam  pis- 
ton or  water  piston  of  the  steam  pump  ? 

Ans.  The  steam  piston  should  have  about  2^ 
times  the  area  of  the  water  piston.  There  being  no 
mechanical  purchase  in  favor  of  the  steam  piston,  it 
must  have  the  greater  area  of  the  two,  otherwise 
the  pressure  on  the  water  piston  would  equal  the 
pressure  on  the  steam  piston  and  the  pump  would 
refuse  to  work.  For  this  reason  all  boiler  pumps 
have  larger  steam  pistons  than  water  pistons. 

(Jues.     What  rule  would  you  give  for  area  of  steam  piston.  ? 
Ans.     Multiply  area  of  water  piston  by  2.75. 


QUESTIONS  AND  ANSWERS.  113 

Ques.  How  would  you  find  the  capacity  of  a  water 
cylinder  of  a  steam  pump  in  gallons  ? 

Ans.  Multiply  the  area  in  inches  by  the  length 
of  stroke  (this  gives  the  capacity  in  cubic  inches). 
Next  divide  by  231  (which  is  the  cubical  contents 
of  a  U.  S.  gallon)  and  the  product  is  the  capacity  in 
U.  S.  gallons. 

Ques.  What  is  the  rule  for  finding  quantity  of  water 
pumped  in  one  minute  running  at  100  feet  of  piston  speed 
per  minute  ? 

Ans.  Square  the  diameter  of  the  water  cylinder 
in  inches  and  multiply  by  4.  The  answer  will  be  in 
gallons. 

Ques.  How  do  you  find  the  horse-power  necessary  to 
pump  water  to  a  given  height  ? 

Ans.  Multiply  the  total  weight  of  the  water  in 
pounds  by  the  height  in  feet  and  divide  the  product 
by  33,000. 

Ques.  How  do  you  find  the  pressure  in  Ibs.,  per  square 
inch,  of  a  column  of  water  ? 

Ans.  Multiply  the  height  of  the  column  of  water 
in  feet  by  .434. 

Ques.  What  is  the  rule  for  finding  the  water  capacity  of 
a  steam  pump  per  hour  ? 

Ans.  ist.  Find  the  capacity  of  the  pump  in  cubic 
inches,  by  multiplying  the  area  by  the  inches  in 
strokes,  and  by  the  fraction  it  is  full. 


114  ENGINEERS1  EXAMINATIONS. 

2d.  Find  the  cubic  inches  of  water  pumped  per 
hour,  by  multiplying  the  contents  of  the  pump  by 
the  strokes  per  minute  and  by  60,  representing  the 
minutes  in  an  hour. 

3d.  Find  the  number  of  the  cubic  feet  of  water  by 
dividing  the  cubic  inches  by  1,728. 

Ques.  In  these  rules  have  you  made  any  allowance  for 
"slippage  "  and  friction  ? 

Ans.     No. 

Ques.    What  must  every  feed  pump  be  designed  to  do  ? 

Ans.  It  must  provide  not  only  the  water  really 
needed  for  the  work,  but  a  large  percentage  addi- 
tional to  cover  waste  due  to  priming,  condensation 
in  the  pipes,  etc. 

Ques.    Give  an  idea  of  amount  of  slippage  ? 

Ans.  In  well  designed  and  well  constructed 
steam  pumps  the  "slippage"  will  be  one-tenth  and 
an  allowance  of  one-quarter  will  be  safe  for  the 
friction  ;  but  if  the  pump  is  old  or  badly  designed 
or  if  the  pump  is  working  against  a  very  high  or  a 
very  low  lift  the  net  loss  should  be  increased  to 
twice  the  percentages  given. 

Ques.  Can  you  give  approximate  rule  for  size  of  pipes  for 
steam  ? 

Ans.  For  the  steam  pipe  divide  the  area  of  steam 
piston  by  64. 


QUESTIONS  AND  ANSWERS.  115 

For  the  exhaust  pipe  divide  the  area  of  steam 
piston  by  32. 

For  the  discharge  pipe  divide  the  area  of  plunger 
by  3- 

For  the  suction  pipe  divide  the  area  of  plunger 
by  2. 

But  as  the  sizes  of  piping  are  of  standard  sizes, 
sizes  can  only  be  approximated,  preference  being 
given  to  the  next  size  larger  than  the  figures  call  for. 

(Jues.  When  pressure  per  square  inch  is  shown  by  the 
guage,  which  is  the  greater  pressure,  that  of  water  or  steam? 

Ans.  There  is  no  difference  between  the  intensity 
of  steam  pressure  and  water  pressure,  a  pound  of 
pressure  is  a  pound  whether  of  steam  or  water. 

(Jues.    What  are  pump  valves  made  of  ? 

Ans.  They  are  made  of  brass,  hard  rubber,  soft 
rubber,  vulcanized  fibre  and  wood. 

Ques.     What  is  to  be  said  as  to  their  size  and  "  lift "  ? 

Ans.  The  valves  should  be  larger  than  the  pipe, 
enough  so  as  to  give  a  clear  waterway,  the  same  area 
as  the  suction  pipes.  The  lift  of  the  valves  should 
be  as  little  as  possible  without  causing  too  much 
frictional  resistance  to  the  water. 

Ques.  For  leakage  of  water  and  steam  priming,  blowing 
off,  loss  by  safety  valve,  etc.,  how  much  water  for  a  station- 
ary engine  should  be  provided  ? 


116  ENGINEER'S  EXAMINATIONS. 

Ans.  From  double  to  two  and  one-half  times  the 
net  feed  water  required  by  the  engines. 

Qnes.     How  much  should  be  allowed  in  marine  engines  ? 

Ans.  To  provide  for  the  discharge  of  the  brine, 
from  three  to  four  times  of  the  net  feed  water  should 
be  provided. 

Qnes.  Of  what  is  water  composed  and  in  what  proper 
tions? 

Ans.  Water  is  composed  of  one  volume  of 
hydrogen  to  two  of  oxygen. 


Ques.  What  are  the  cubic  contents  and  weight  of  a  cubic 
foot  of  water  ? 

Ans.  i  cubic  foot  equals  7^2  gallons  (1,728  cubic 
inches)  and  weighs  62^2  Ibs.  A  gallon  thus  has  231 
cubic  inches  and  weighs  8J4  Ibs. 

Ques.  What  is  the  rule  for  finding  the  water  capacity  of 
the  horizontal  steam  boiler  ? 

Ans.  i.  Multiply  two-thirds  of  the  area  of  the 
head,  in  inches,  by  the  length  of  the  boiler  in  inches. 

2.  Deduct  the  area  of  a  single  tube  multiplied  by 
the  number  in  the  boiler,  multiplied  by  the  length 
in  inches. 

3.  Divide  by  231  to  reduce  the  answer  to  gallons. 


QUESTIONS  AND  ANSWERS.  11? 


THE  INJECTOR  OR  INSPIRATOR. 


This  boiler  fixture  was  an  invention  of  Gifford,  and  is  one 
of  the  most  peculiar  and  interesting  appliances  connected 
with  the  steam  plant. 

It  is  simply  an  instrument  for  allowing  steam  to  rush  from 
a  boiler,  and  to  suck  up  and  mix  with  itself  a  stream  of  cold 
water,  by  which  it  is  condensed,  and  to  which  it  imparts  so 
much  of  its  own  velocity,  that  the  combined  mass  of  water 
and  condensed  steam  enters  into  and  feeds  the  boiler. 

Injectors  are  used  also  to  pump  out  cisterns  and  drain 
basins  and  have  even  been  used  to  pump  out  mines. 


Questions  and  Answers  Relating  to  the 
Steam  Injector. 

Ques.  What  is  the  main  difference  between  the  steam 
pump  and  the  injector  ? 

Ans.  The  pump  has  moving  parts  and  is  a  regu- 
lar machine,  while  the  injector  has  no  moving 
mechanism  whatever. 

Ques.  Whence  comes  the  power,  used  in  forcing  water 
into  the  boiler  by  an  injector  ? 


118  ENGINEERS'  EXAMINATIONS. 

Ans.  To  the  difference  in  the  velocity  of  the 
escaping  steam  from  a  boiler  under  pressure  and  the 
velocity  acquired  by  water  from  the  same  boiler  and 
under  the  same  pressure  and  at  the  same  time. 

Ques.  About  what  is  the  difference  in  the  speed  of  the 
two? 

Ans.  The  steam  has  a  velocity  of  sixteen  or 
eighteen  times  that  of  the  water — this  varies  with 
the  pressure. 

Ques.    How  should  the  instrument  be  connected  ? 

Ans.  It  should  be  so  placed  that  it  will  take 
steam  from  the  highest  point  in  the  boiler.  A  valve 
should  be  put  in  the  steam  pipe  just  above  the 
injector  and  a  check  and  globe  valve  between  it  and 
the  boiler,  also  a  globe  valve  in  the  supply  pipe  ;  if 
the  feed  is  delivered  through  a  heater,  place  a  check 
between  it  and  the  injector.  It  is  better  to  have  the 
suction  pipe  one  size  larger  than  the  connection 
with  the  boiler,  especially  in  case  of  a  high  lift. 

Ques.  What  are  essential  to  the  successful  operation  of 
the  instrument  ? 

Ans.  The  suction  pipe  should  be  absolutely  air- 
tight ;  the  lift  should  not  exceed  25  feet  with  a 
temperature  of  about  no  degrees  and  not  more 
than  140  degrees  for  a  low  lift. 

Ques.  Will  the  injector  work  if  the  water  supplied  to  it  is 
too  hot? 


QtTESTIONS   AND   ANSWERS.  119 

Ans.  No.  Because  the  colder  the  water  the 
quicker  and  more  thoroughly  is  the  steam  turned 
into  water  of  condensation  ready  to  join  in  the  flow 
towards  the  boiler. 

(Jues.  Does  the  injector  "  suck  up  "  or  lift  the  water  that 
it  forces  into  the  boiler  ? 

Ans.  No  more  than  a  pump  does  ;  for  both  appa- 
ratuses simply  remove  the  air  from  the  supply  pipes 
and  the  weight  of  the  atmosphere  pushes  the  water 
forward. 

(Jnes.    What  are  injector-nozzles  ? 

Ans.  They  are  tubes  with  ends  rounded  to 
receive  and  deliver  the  fluids  with  the  least  possible 
loss  by  friction  and  eddies. 

Ques.    What  are  double  injectors  ? 

Ans.  They  are  those  in  which  the  delivery  from 
one  injector  is  made  the  supply  of  the  second.  The 
double  injector  makes  use  of  two  sets  of  nozzles,  the 
"lifter"  and  "forcer."  The  lifter  draws  the  water 
from  the  reservoir  and  delivers  it  to  the  forcer, 
which  sends  it  into  the  boiler. 

Qnes.    What  is  the  exhaust  steam  injector  ? 
Ans.     It  is  different  from  others  in  that  it  uses 
the  exhaust  steam  from  a  non-condensing  engine. 

(Jues.  What  has  been  the  objection  to  the  greater  adoption 
of  this  form  of  injector  ? 

Ans.  It  carries  over  into  the  boiler  the  waste 
steam  from  the  cylinder. 


120  ENGINEERS'  EXAMINATIONS. 


THE  INDICATOR. 


This  device,  invented  by  James  Watt  more  than  a  century 
ago,  is  an  ingenious  tell-tale  of  what  goes  on  in  the  steam- 
cylinder.  A  knowledge  of  its  operation  is  necessary  to 
obtain  a  high-grade  license. 

All  indicators  are  practically  of  the  same  construction  and 
act  upon  the  same  principle.  Each  consists  of  a  small 
cylinder  accurately  bored  out  and  fitted  with  a  piston  capable 
of  working  in  the  cylinder  with  little  or  no  friction ;  the  pis- 
ton rod  is  attached  to  a  pah*  of  light  levers,  at  the  end  of  one 
of  which  is  carried  a  pencil  designed  to  move  perpendicu- 
larly. The  motion  of  the  piston  in  the  cylinder  is  f  f  of  an 
inch  and  the  area  of  the  piston  is  exactly  %  square  inch. 

The  pressure  of  the  steam  is  recorded  by  the  pencil  at  all 
points  of  the  stroke  as  the  piston  moves  to  and  fro,  on  a 
piece  of  paper  secured  to  a  revolving  drum.  The  motion  of 
the  piston  is  controlled  by  springs  of  known  tension,  several 
of  which  are  furnished  with  each  instrument ;  each  spring  is 
marked  to  show  at  what  boiler  pressure  of  steam  it  is  to  be 
used. 

The  only  absolute  information  any  indicator  can  convey, 
whatever  its  form,  is  the  pressure  in  the  cylinder  of  the 
engine ;  all  the  other  information  to  be  had  from  it  comes 


QUESTIONS  AND  ANSWERS.  121 

through  a  process  of  reasoning  based  upon  experience  and 
observation. 

In  order  that  the  diagram  should  be  correct  it  is  essential, 
first,  that  the  motion  of  the  drum  and  paper  shall  coincide 
exactly  with  that  of  the  engine-piston,  and  that  the  motion 
of  the  pencil  shall  also  correspond  with  the  other  motions 
described. 


Questions   and  Answers  Relating  to  the 
Indicator. 

Ques.     What  is  an  indicator  card  ? 

Ans,  It  is  a  paper  wound  round  the  cylinder  of 
the  indicator  upon  which  the  pencil  has  drawn  the 
lines  indicating  the  work  done  by  the  steam  in  the 
cylinder.  The  extreme  length  of  the  diagram  may 
be  5^  inches. 

(Jues.    What  is  the  steam-line  ? 

Ans.  It  is  the  line  on  the  card  which  shows  the 
place  of  admission  to  beginning  of  cut-off. 

(Jues.    What  is  the  exhaust  line  ? 

Ans.  It  is  that  part  of  the  diagram  which  shows 
the  point  of  exhaust. 

(Jties.    What  is  the  expansion  line  ? 

Ans.  It  is  that  part  showing  the  curve  of 
expansion;  /.  e.,  the  movement  between  the  cut-off 
and  the  exhaust. 


122  ENGINEERS'  EXAMINATIONS. 

Ques.  What  base  line  is  always  assumed  in  figuring  the 
indicator  card  ? 

Ans.  All  figures  are  made  from  absolute  vacuum, 
or  i4rV  Ibs.  per  sq.  inch  below  atmospheric  pressure. 

Ques.    Why? 

Ans.  For,  from  the  line  of  absolute  vacuum  are 
made  up  all  tables  of  weight,  volume,  expansion 
and  all  other  properties  of  steam. 

Ques.    What  four  points  does  an  indicator  show  ? 

Ans.  Highest  and  .lowest  pressure,  cut-off  and 
lead. 

Ques.  How  can  you  determine  whether  the  steam  is 
"wire-drawn  "? 

Ans.  If  the  steam  is  "  wire-drawn "  the  steam 
line  will  fall  as  the  piston  advances. 

Ques.    What  is  done  when  steam  is  cut-off  at  6  inches  ? 

Ans.  When  the  piston  has  travelled  6  inches  the 
valve  closes,  cutting  off  the  live  steam,  and  the 
remainder  of  the  work  in  the  cylinder  is  done  by 
the  expansion  of  the  steam  previously  admitted. 

Ques.  What  do  you  understand  by  the  number  of  an 
indicator  spring  ? 

Ans.  The  number  marked  on  a  spring  (several 
of  which  are  furnished  with  each  indicator)  is 
designed  to  show  the  number  of  Ibs.  steam  pressure 
on  the  boiler  at  which  it  is  to  be  used  :  thus  a  30  Ib. 


QUESTIONS  AND  ANSWERS.  123 

spring  is  one  in  which  a  pressure  of  30  Ibs.  will 
cause  the  piston  inside  the  indicator  to  rise  one 
inch  above  the  atmospheric  line  of  the  diagram.* 

Ques.    What  is  an  indicator  diagram  ? 

Ans.  It  is  the  figure  drawn  by  the  pencil  attached 
to  the  indicator  from  which  the  mean  effective 
pressure  in  the  cylinder  is  calculated. 

Ques.     How  is  this  done  ? 

Ans.  By  first  dividing  the  diagram  into  ten  equal 
spaces  by  drawing  perpendicular  lines  to  the  atmos- 
pheric line  called  ordinates.  Any  number  of  ordi- 
nates  may  be  used  but  it  is  customary  to  use  icx 

2.  The  two  end  ordinates  should  be  only  half  the 
distance  from  the  ends  of  the  diagram  that  they  are 
from  the  next  ordinate,  because  the  ordinate  is  the 
middle  of  the  space  it  occupies. 

3.  The  ordinates  being  drawn    their  lengths  are 
added  together  and  the  sum  so  obtained  is  divided 
by  the  number  (10)  which  gives  the  average  heighth. 

4.  If  a  30  Ib.  spring  has  been  used  and  the  average 
heighth   of   the    ordinates   is    i*4  inches,  then    the 


*  The  strength  of  the  spring  is  so  adjusted  as  to  cause  the  diagram 
to  be  about  2J4  inches  high,  let  the  steam  pressure  be  what  it  may. 
The  following  are  the  scales  of  springs  to  be  used  in  the  Thompson 
Indicator : 

Scale  of          Used  for  pressure  above  atmosphere 
Spring.  if  not  more  than 

15  Ibs.       .       .       .        21  Ibs.  per  sq.  in. 

30  "          ...        38   "      ' 

80  "         ...        94  "     "    "    " 
60  "         .       .      .      143  "•»•** 


124  ENGINEERS'  EXAMINATIONS. 

average  pressure  of  steam  in  the  cylinder  shown  by 
the  diagram  is  45  Ibs. 

Qucs.  Having  found  the  average  pressure  in  the  cylinder, 
how  do  you  proceed  to  get  the  indicated  horse  power  (I.  H.  P.)  ? 

Ans.  By  multiplying  the  travel  of  the  piston  in 
feet  and  the  area  of  the  piston  in  inches;  2,  multi- 
plying the  product  by  the  mean  average  pressure  in 
Ibs. — in  the  case  given  ;  45  Ibs. — and  dividing  by 
33,000. 

(Jues.  What  have  you  to  say  as  to  calculating,  by  the 
indicator,  the  amount  of  water  and  steam  used  from  the 
boiler  ? 

Ans.  Experience  shows  that  the  full  amount  of 
water  used  cannot  be  accounted  for,  owing  to  its 
being  unduly  saturated,  the  cooling  of  the  cylinder, 
etc.,  hence  the  calculations  made  are  unsatisfactory. 

Qnes.  Is  there  an  easy  way  of  getting  the  lengths  of  the 
ordinates  ? 

Ans.  Yes.  Take  a  long  strip  of  paper,  say  half 
an  inch  wide  and  10  or  20  inches  long,  according  to 
the  nature  of  the  card,  mark  a  starting  place  on  the 
edge  near  one  end;  then  lay  the  strip  of  paper  along 
the  first  dotted  line,  and  mark  off  the  length  of  that 
line  ;  then  lay  it  on  the  second  space  so  as  to  add 
the  length  of  the  second  line  to  the  first  line;  and  so 
on  until  the  tenth  (dotted  line)  ordinate  is  added, 
the  whole  being  in  one  length,  end  to  end. 

Now  take  a  rule  and  read  off  how  many  inches 
there  are  in  the  whole  length,  and  divide  them  by  ten. 


QUESTIONS  AND  ANSWERS.  125 

Ques.  What  instrument  has  been  invented  and  introduced 
to  get  the  mean  effective  pressure  as  shown  by  a  diagram  ? 

Ans.  A  planimeter.  No  skill  or  mathematical 
knowledge  are  necessary  to  use  this  instrument. 
The  readings  taken  from  a  counter  on  the  instru- 
ment give  the  area  of  the  enclosed  figure. 

(Jues.  What  is  the  difference  between  the  Indicated  Horse 
Power  (I.  H.  P.)  and  the  Effective  Horse  Power  (E.  H.  P.)? 

Ans.  The  effective  horse  power  is  the  indicated 
horse  power  less  the  engine  friction  ;  it  is  always 
less  from  the  fact  that  the  engine  itself  absorbs 
power. 

Ques.  What  proportion  of  the  indicated  power  does  the 
engine  consume  ? 

Ans.  With  well  constructed  engines  and  every- 
thing in  good  working  order  it  is  probably  under 
ten  per  cent. — but  with  the  ordinary  unbalanced 
slide  valves  and  bad  construction  one-third  of  the 
power  is  wasted. 

Ques.    Does  a  correct  curve  always  show  an  economical 

engine  ? 

Ans.  No,  because  a  defective  leakage  may  be 
the  same  on  both  sides — the  leakage  out  may  balance 
the  leakage  in — hence  it  must  be  carefully  assured 
that  the  piston  and  valves  are  tight. 

Ques.    Does  a  defective  diagram  always  indicate  trouble  ? 

Ans.  Yes,  a  diagram  with  an  incorrect  curve 
necessarily  and  infallibly  shows  a  wasteful  engine. 


126  ENGINEERS'  EXAMINATIONS. 


ELECTRICITY  FOR  ENGINEERS. 


The  latest  developments  of  engineering  are  without  a 
doubt  along  electric  lines,  and,  in  issuing  a  license  for  a 
steam  plant  where  there  is  an  electrical  apparatus,  the  Ex- 
aminer will  insist  upon  some  knowledge  and  practical  ex- 
perience in  industrial  electricity — and  the  devices  employed 
to  utilize  it  before  granting  a  license. 

The  Electric  current  (so-called)  is  produced  by  a  machine 
known  as  a  Dynamo  or  Electric  Generator  ;  this  might  be 
called  the  Steam  Engine  of  Electricity  as  it  simply  transmits 
or  carries  along  the  power,  produced  elsewhere,  to  its  speci- 
fied work. 

It  is  with  the  Dynamo  that  the  Licensed  engineer  and  his 
assistants  has  primarily  to  do,  and  it  is  necessary  that  he  have 
a  mastery  of  it — in  the  same  degree  that  he  has  of  his  engine. 
It  is  true  that  in  the  Power  Stations  of  Electric  Railways 
and  other  large  plants  that  Electricians,  so  ranked  are  con- 
stantly on  watch,  but  it  is  generally  true  that  the  Engineer 
has  charge  of  the  Electric  apparatus. 

Next  to  the  Dynamo  the  Engineer  must  be  informed  as  to 
the  Laws  of  the  Transmission  of  the  Electric  Current — in 
practical  language  he  must  understand  "  Wiring. " 

The  recent  great  advance  in  the  practical  development  of 
Electricity  has  come  from  the  discovery  of  the  Electric  Motor 


QUESTIONS  AND  ANSWERS.  137 

—which  is  simply  a  Dynamo  reversed — while  the  Dynamo  is 
run  by  a  belt  or  other  mechanical  means,  the  Motor  is  run 
by  the  electric  current.  A  practical  acquaintance  with  one 
answers  for  both  the  Dynamo  and'  the  Motor,  although  there 
are  some  points  of  difference  necessary  to  be  known. 

What  is  electricity  is  a  question  often  asked,  but  which 
has  never  yet  been  satisfactorily  answered.  It  is  one  of  the 
unexplained  existences  which,  like  latent  heat,  are  known  to 
be,  but  aside  from  their  mighty  and  beneficial  accomplish- 
ments might  as  well  remain  unknown. 

How  electricity  is  "gathered"  and  how  it  is  utilized  in 
some  of  the  many  machines  now  in  use  is  the  limit  of  neces- 
sary knowledge  concerning  it. 

It  is  well  to  remember  at  the  beginning  that  magnetism  is 
almost  indentical  with  electricity,  and  that  the  way  in  which 
a  small  magnet  will  attract  and  hold  a  bit  of  iron  or  steel  (a 
tack  or  nail)  is  the  A  B  C  of  the  science.  Next,  that  iron  or 
steel  are  the  principal  metals  (with  copper  wire)  with  which 
the  greatest  as  well  as  the  least  of  the  electrical  problems 
are  worked  out  to  a  commercial  and  industrial  success. 


Questions  and  Answers  Relating  to  Electric- 
ity and  Electric  Machines. 

Qucs.    What  is  an  electric  current  ? 

Ans.  It  is  something  which  seems  to  flow  along 
or  through  the  conducting  wires  ;  although  not 
known  as  to  its  nature  it  is  freely  called  the  electric 
current. 


138  ENGINEERS'   EXAMINATIONS. 

Qnes.    How  many  kinds  of  electricity  are  there  ? 

Ans.  One — although  it  is  spoken  of  and  treated 
as  two,  positive  and  negative. 

Ques.    How  are  these  designated  ? 

Ans.  By  the  plus  sign  -f  for  positive  and  the 
negative  sign  —  for  the  negative  electricity.  These 
signs  are  very  useful  in  designating  the  two. 

Ques.    How  do  these  stand  in  relation  to  each  other  ? 

Ans.     It   is   said    that  -f-  electricity   attracts   - 
electricity,  and  that  —  electricity  attracts  +  an^  tne 
contrary,  +  repels  +,  —  repels  — . 

Ques.     How  do  these  currents  flow  ? 

Ans.  Positive  (-f )  electricity  and  ( — )  electricity 
mean  but  a  difference  in  pressure,  always  flowing 
from  +  to  —  as  steam  always  flows  through  the 
steam  pipe,  engine  and  exhaust  and  never  backward. 
It  is  impossible  to  generate  a  current  of  negative  ( — ) 
electricity  of  a  higher  pressure  than  the  (-J-)  positive 
current. 

Qnes.    What  is  a  conductor  ? 

Ans.  Anything  that  will  allow  the  electric  cur- 
rent to  flow  freely  through  it.  All  the  lines  (wires) 
carrying  electricity  are  conductors,  hence  any- 
thing which  allows  the  free  passage  of  electricity  is 
a  conductor,  and  anything  which  prevents  the 
passage  of  electricity  is  a  non-conductor. 


QUESTIONS    AND    ANSWERS.  129 

Ques.    Which  is  the  most  important  ? 

Ans.  It  is  just  as  necessary  in  practical  work  to 
have  good  non-conductors  as  it  is  to  have  good 
conductors.* 

(£ues.     Name  some  of  the  conductors. 

Ans.  The  ground  is  a  good  conductor,  which 
fact  often  causes  great  "trouble."  Water  is  a 
conductor,  and  if  the  wires  and  their  supports  are 
wet,  and  if  there  are  any  conducting  substances  that 
will  allow  the  passage  of  current  to  the  ground, 
there  is  trouble  again.  Other  conductors  are  silver, 
copper,  iron,  etc.f 

Ques.     Name  some  non-conductors  ? 

Ans.  Dry  air,  glass,  silk,  asbestos,  woolen  and 
cotton  cloth,  dry  paper,  dry  wood,  oils. 

Ques.  What  substances  are  generally  used  for  non-con- 
ductors ? 

Ans.  Cotton  or  silk,  coated  with  paint,  varnish 
or  asphaltum  ;  the  cotton  and  silk  are  the  non- 
conductors, and  the  varnish,  etc.,  are  put  over  all  to 
keep  away  the  moisture. 


*  All  substances  will  allow  of  the  passage  of  some  electricity,  but 
as  there  are  substances  that  offer  a  very  strong  resistance  to  its  pass- 
age they  are  generally  called  insulators,  or  simply  non-conductors. 

t  Silver  is  six  times  as  good  a  conductor  as  iron,  that  is,  if  you  take 
a  silver  wire  and  an  iron  wire  the  current  will  pass  through  the  silver 
wire  six  times  as  easy  as  through  iron.  Lead  will  only  conduct  one- 
eleventh  as  well  as  silver. 


130  ENGINEERS'  EXAMINATIONS. 

Ques.  "What  is  one  of  the  most  important  points  in  keeping 
up  electric  machines  and  circuits  ? 

Ans.  To  keep  the  circuits  well  insulated  and  to 
allow  no  accumulation  of  oil  and  dirt  around  the 
machines  to  form  a  conducting  substance.  Lamps 
and  dynamos  must  also  be  kept  clean  so  that  they 
work  freely.  Gas,  moisture,  and  steam  are  to  be 
watched  for,  as  they  all  destroy  the  necessary  insu- 
lation. 

Ques.    What  is  a  dynamo-electric  machine  1 

Ans.  It  is  a  machine  driven  by  power,  usually  by 
stearn  or  water,  used  to  convert  mechanical  power 
into  electrical  energy. 

Ques.    Describe,  generally,  the  construction  of  a  dynamo. 

Ans.  There  are  various  styles  of  dynamos,  but 
they  are  all  built  upon  similar  principles.  First, 
there  is  the  magnet  core,  usually  made  of  wrought 
iron  ;  second,  around  the  core  are  wound  field  coils 
— the  field  coil  is  copper  wire  generally  insulated 
with  soft  cotton  thread  and  double-wound  ;  third, 
pole  pieces,  usually  made  of  cast  iron,  into  which 
the  magnetic  core  is  cast ;  the  round  space  between 
the  pole  pieces  is  the  magnetic  field — so  called 
because  it  is  there  that  the  lines  of  magnetic  force 
cross  from  one  pole  to  the  other,  and  where  the  arm- 
ature is  placed  ;  the  pole  pieces  are  united  by,  fifth, 
a  "yoke,"  which  completes  the  magnetic  current; 
this  is  practically  an  electro  magnet  of  the  horse- 
shoe form,  with  the  wire  wound  on  near  the  poles,, 


QUESTIONS  AX1)  ANSWERS.  131 

({ues.    What  is  the  meaning  of  the  term  insulated  ? 

Ans.  This  means  removed  from  the  sensation  of 
touch,  handling  or  feeling — rendered  insensible  to 
touch. 

Ques.  What  is  the  object  of  insulating  the  wire  of  electro 
magnets  ? 

Ans.  So  as  to  form  lines  of  travel  for  the  mag- 
netic force. 

(jues.  What  would  be  the  effect,  if,  through  imperfect 
insulation,  the  wires  of  the  magnetic  coil  came  into  contact 
at  some  point  or  other  ? 

Ans.  It  means  so  much  loss,  and  if  the  insula- 
tion is  too  imperfect  the  whole  circuit  will  have  to 
be  abandoned  or  newly  insulated. 

(}ues.  Is  there  any  difference  in  the  names  of  the  poles  in 
permanent  and  electro  magnets  ? 

Ans.  In  a  magnet  the  pole  into  which  the  lines 
of  force  are  assumed  to  enter  is  called  the  south 
pole ;  the  pole  from  which  they  are  assumed  to 
emerge  is  called  the  north  pole — in  other  words  the 
north  pole  is  positive  and  the  south  pole  negative. 

(Jues.    What  is  a  permanent  magnet  ? 

Ans.  It  is  a  bar  of  U-shaped  steel  which  con- 
tinues magnetized  for  an  indefinitely  long  time. 

Ques.    What  is  an  electro  magnet  ? 

Ans.  It  is  a  body  of  iron  which  becomes  ja.agne- 
tized  by  the  electric  current  passing  around  it 


EXAMINATIONS. 


conducted  by  insulated  wires  —  it  is  the  opposite  of  a 
permanent  magnet  because  upon  stopping  the 
machine  the  magnetic  condition  ceases. 

Ques.    What  is  a  switch  ? 

Ans.  A  switch  is  a  device  used  to  make  or  break 
a  circuit  —  the  switch  is  so  arranged  that  the  hand 
will  start  it,  while  a  powerful  spring  throws  the 
switch  open  or  closes  it  immediately. 

Ques.    What  is  a  brush  ? 

Ans.  This  consists  of  a  quantity  of  straight 
copper  wires  laid  side  by  side,  soldered  together  at 
one  end  and  held  in  a  suitable  clamp  ;  two  layers  of 
wires  are  often  thus  united  in  a  single  brush. 

Brushes  are  also  made  of  broad  strips  of  springy 
copper,  slit  for  a  short  distance,  so  as  to  touch  at 
several  points. 

Ques.    What  is  the  object  of  slitting  the  brush  ? 

Ans.  The  subdividing  of  the  spark  at  the 
contact. 

Ques.  What  rule  do  you  consider  important  relating  to 
the  brushes  ? 

Ans.  A  brush  should  never  be  lifted  off  the 
commutator  while  the  dynamo  is  running. 

Ques.    When  do  the  brushes  cause  '  '  flashing  "  ? 

Ans.  When  they  are  out  of  position,  too  far 
ahead  or  too  far  back  or  not  set  directly  opposite 
each  other  ;  if  the  brushes  do  not  have  sufficient 
contact,  a  machine  will  frequently  flash. 


QUESTIONS  AND  ANSWERS  133 

(Jues.    What  is  the  use  of  the  commutator  ? 

Ans.  The  commutator  or  collector  of  a  dynamo 
is  used  for  changing  the  alternating  currents,  as 
produced  in  the  armature,  to  continuous  currents  as 
delivered  to  the  lines.  The  commutator  transfers 
these  currents,  as  they  are  formed,  to  the  brushes, 
which  convey  them  to  the  lines  continuously  in  one 
direction. 

(Jues.    What  is  the  commutator  ? 

Ans.  In  general,  a  cylinder  madf  up  of  alternate 
sections  of  conducting  and  non-conducting  substan- 
ces, running  parallel  with  the  shaft  of  the  machine 
upon  which  it  turns. 

(Jues.  What  may  be  said  about  the  trouble  caused  by  the 
dynamo  ? 

Ans.  In  the  commutator  and  brushes  will  be 
found  the  greater  part  of  the  difficulties  that  the 
engineer  in  charge  of  the  dynamo  has  to  contend 
with  in  his  electric  plant. 

(Jues.  What  is  the  difference  between  an  incandescent 
light  and  an  arc  light  ? 

Ans.  The  incandescent*  light  is  produced  by 
passing  electricity  through  a  carbon  ribbon  or  fila- 
ment confined  in  a  vacuum  ;  an  arc  light  is  produced 
by  passing  electricity  through  two  carbon  pencils 
slightly  separated,  in  open  air. 

*  Incandescent  means  white.  The  electricity  passing  between  the 
points  forms  an  "arc  "  or  curved  line.  Hence  the  name,  arc  light. 


134  ENGINEERS'  EXAMINATIONS. 

Questions  and  Answers    Relating  to  Gravity 
and  Strength  of  Materials. 

Qnes.     What  is  gravity  ? 

Ans.  It  is  an  unexplained  force  which  draws 
every  particle  of  matter  toward  every  other  particle. 
It  extends  to  all  known  bodies  in  the  universe,  from 
the  smallest  to  the  greatest* 

Qnes.    What  is  specific  gravity  ? 

Ans.  Every  substance  in  nature  has  a  weight 
specific  —  or  peculiar  —  to  itself.  For  example,  pine 
wood  has  a  certain  weight  and  cast-iron  has  another 
certain  weight,  hence,  the  specific  gravity  of  a  body 
is  its  weight  compared  with  the  weight  of  another 
body  taken  as  a  standard. 

Qnes.  What  is  the  accepted  standard  for  all  «olids  and 
liquids  ? 

Ans.     Water. 

Qnes.    What  is  the  standard  of  comparison  for  all  gases  ? 
Ans.     Air. 

Ques.  When  we  say  that  the  specfic  gravity  of  iron 
(wrought)  is  7.688,  what  do  we  mean  ? 

Ans.  That  it  is  seven  times  as  heavy  as  water 
and 


*  The  heaviest  of  all  known  substances  is  platinum,  whose  specific 
gravity  is  22,  water  1  ;  and  the  lightest  of  all  weighable  bodies  is 
hydrogen  gas,  whose  specific  gravity  is  wtfk  common  air  being  1,  but 
air  is  818  lighter  than  water.  Hence,  by  calculation,  it  will  be  found 
that  platinum  is  247,000  times  heavier  than  hydrogen,  and  a  wide  range 
is  allowed  to  the  various  bodies  which  lie  between  these  extremes. 


QUESTIONS  AKt>  AtfSWB&S. 


Ques.    How  may  weight  be  defined  ?    What  is  it  ? 

Ans.  The  weight  of  a  body  is  the  force  it  exerts 
in  consequence  of  its  gravity.  We  weigh  a  body  by 
measuring  the  force  required  to  hold  it  back,  or  to 
keep  it  from  descending,  hence  weights  are  nothing 
more  than  measures  of  the  force  of  gravity  in  differ- 
ent bodies. 

({lies.  What  is  that  principle  which  holds  bodies  together 
called? 

Ans.  It  is  the  strength  of  cohesion  ;  this  is  the 
power  residing  in  the  minute  particles  of  matter, 
called  molecules,  to  cling  together. 

Ques.  Name  four  ways  in  which  this  cohesion  may  be 
overcome  in  a  bar  of  iron  or  piece  of  timber,  and  the  common 
names  of  the  forces  used  ? 

Ans.  i.  The  bar  may  be  pulled  asunder  ;  resist- 
ance to  this  force  is  called  tensile  strength. 

2.  The  iron  may  be  crushed  in  the  direction  of  its 
length.     This  is  direct  thrust  or  compression,  and 
the  resistance  to  it  is  called  the  crushing  strength. 

3.  The  bar  may  be  bent  or  broken  from  the  direc- 
tion of  the  middle  or  side.     This  is  transverse  strain 
or  flexion,  and  resistance  to  it  is  called   transverse 
strength. 

4.  The  bar  may  be  twisted  off  ,  this  is   torsion  : 
resistance  to  it  is  tortional  strength. 

Ques.     Define  stress  and  strain. 

Ans.  Any  bending  or  breaking  pressure  is  a 
stress  ;  its  effect  on  the  piece  is  a  strain  ;  hence  the 


ENGINEERS'  EXAMINATIONS. 


strength  of  a  solid  piece  or  body  is  the  total  resist- 
ance it  can  oppose  to  strain  in  that  direction. 

Qnes.    What  is  the  Hydrometer  ? 

Ans.  It  is  an  instrument  constructed  for  the 
especial  purpose  of  ascertaining  the  specific  gravities 
of  liquids. 

Ques.    How  may  the  specific  gravity  of  solids  be  found  ? 

Ans.  Advantage  may  be  taken  of  the  important 
fact  that  when  a  body  is  wholly  immersed  in  water, 
it  displaces  a  bulk  of  that  liquid  exactly  equal  to  its 
own,  hence  the  difference  of  its  weight'  in  water 
from  that  of  its  weight  in  air  must  be  the  weight  of 
an  equal  bulk  of  water. 

Ques.    What  is  a  Salinometer  ? 

Ans.  It  is  a  glass  or  metal  instrument,  by  means 
of  which  the  density  of  water  is  ascertained.  In 
plain  language  it  is  a  salt  measure  or  hydrometer. 

Ques.  What  is  the  amount  of  salt  held  in  solution  in  sea 
water? 

Ans.  One  thirty-third  (iV).  This  quantity  is 
called  one  degree,  and  if  the  water  of  a  marine 
boiler  tested  by  the  instrument  shows  ^,  it  is 
expressed  by  saying  "two  degrees",  if  &,  then 
three  degrees,  etc. 

Ques.    How  are  the  Salinometers  graduated  ? 

Ans.  Some  into  33ds,  and  some  into  32ds,  each> 
representing  about  five  ounces  of  salt  to  a  gallon  of 
water.* 

*  Nans,  i.  6.,  each  33d  has  503  salt,  T&-  has  1,003,  -fa  has  1^02,  etc. 


QtTESTiONS  AND  ANSWERS. 


137 


Ques.  In  the  use  of  the  Salinometer  where  should  care  be 
used? 

Ans.  They  should  be  used  on  water  taken  from 
the  boiler  almost  as  soon  as  it  ceases  to  boil,  as  200° 
is  the  usual  temperature  at  which  these  instruments 
are  tested,  and  as  the  density  of  fluids  vary  accord- 
ing to  their  temperature. 


TABLE  OF  SPECIFIC  GRAVITIES. 


Iron(cast) 7.207 

"    (wrought) 7.688 

Steel  (soft) 7.780 

"    (tempered) 7.840 

Lead  (cast) 11.400 

"    (sheet) 11.407 

Brass  (cast) 8.384 

"      (wiredrawn)...  8.544 

Copper  (sheet) 8.767 

"      (cast) 8.607 

Gold  (cast) 19.238 

' '    (hammered) 19. 361 

"    (22  carats) 17.481 

"    (20       "    ) 15.709 

Silver  (pure,  cast). . .  .10.474 
"     (hammered)....  10. 511 

Mercury  (60°) 13.580 

Tin 7.293 

Zinc  (cast) 7.215 

Bronze  (gun  metal) ...  8. 700 
Coal  (Bituminous)....  1.256 
.436 
.640 


(Anthracite)  . . .  j  *' ' 


Charcoal 441 

Brick 1.900 

Clay 1.930 

Common  Soil 1.984 

Emery 4.000 

Glass 3.248 

Grindstone 2.143 

Gypsum 2.168 

Lime 2. 720 

Granite 2.625 

Marble 2.708 

Mica 2.800 

Millstone 2.484 

Nitre 1.900 

Porcelain 2.385 

Phosphorus 1.770 

Pumice  Stone 915 

Salt 2.130 

Sand 1.800 

Slate 2.672 

Sulphur 2.033 


tUTQIflEllRS' 


HORSE  POWER  (H.  P.) 


The  capacity  of  work  of  a  steam  engine,  a  steam  boiler, 
or  of  a  whole  steam  plant  is  reckoned  in  horse  power.  The 
abbreviation  of  the  term  is  H.  P. 

A  horse  power  is  33,000  foot-pounds,  or  in  other  words, 
33,000  pounds  lifted  1  foot  high  in  1  minute,  or  550  pounds 
lifted  1  foot  in  1  second  of  time,  hence 

A  foot-pound  is  one  pound  moved  upward  one  foot. 
Example,  work  done  by  lifting  30  pounds  through  a  height 
of  50  feet  =  1,500  foot-pounds. 

While,  by  means  of  the  Indicator,  the  horse  power  of  the 
steam  engine  can  be  determined  to  a  nicety,  the  horse  power 
of  the  steam  boiler  is  almost  an  unknown  quantity ;  it  has 
been  agreed  upon,  however,  to  consider  the  evaporation  of 
80  Ibs.  of  water  in  1  hour  to  be  the  standard  of  efficiency.* 

Ques.  What  are  the  three  kinds  of  horse  power  spoken 
and  written  about,  which  engineers  should  learn  to  dis- 
tinguish ? 

Ans.     Nominal,  Indicated  and  Effective. 

*  The  several  tests  made  on  the  boilers  used  in  the  recent  Chicago 
Exposition  tend  to  prove  that  there  has  been  no  improvement  in  the 
maximum  efficiency  of  boilers  since  1876.  But  boilers  are  now  made 
which  carry  high  pressure  as  safely  as  were  the  pressures  of  1876  by 
the  boilers  then  made. 


QUESTIONS    AND    ANSWERS.  189 

Ques.    What  is  the  difference  between  these  ? 

Ans.  The  nominal  (N.  H.  P.)  is  only  used  as  a 
general  statement  describing  the  dimensions  of  a 
steam  engine  for  convenience  of  makers  and  pur- 
chasers of  steam  engine.  2d,  the  indicated  (I.  H.  P.) 
is  the  "calculated"  work  done  within  the  cylinder. 
3d,  the  effective  (E.  H.  P.)  is  the  work  an  engine 
can  do  after  deducting  the  amount  required  to  drive 
the  engine  when  it  is  running  unloaded.  The  letters 
in  brackets  sLow  the  abbreviations  of  the  terms. 

CJnes.  How  is  the  horse  power  of  the  boiler  best  deter- 
mined?* 

Ans.  The  only  sure  method  is  by  the  actual 
measurement  of  the  water  evaporated. 

Ques.  In  getting  this  measurement  what  precautions 
should  be  taken  ? 

Ans.  Even  when  the  amount  of  water  intro- 
duced and  the  quantities  passed  off  from  the  boiler 
are  accurately  known,  there  yet  remains  a  doubt  as 
to  how  much  has  been  actually  evaporated,  and  how 
much  may  have  passed  off  in  priming,  unless  the 
trial  has  been  conducted  with  the  boiler  open  to  the 
atmosphere.  To  have  the  boiler  thus  open  appears 
to  be  the  only  condition  under  which  accuracy  can 
be  insured,  unless  a  suitable  apparatus  can  be  pro- 
vided for  accurately  measuring  the  weight  and  tem- 
perature of  all  the  steam  and  water  given  off,  when 
the  boiler  is  working  above  atmospheric  pressure. 

*  For  the  rule  for  calculating  the  horse  power  of  the  Steam 
Engine,  see  cages  79  and  80. 


140  ENGINEERS'  EXAMINATIONS. 

Ques.    Can  any  boiler  be  said  to  be  free  from  priming  ? 

Ans.  There  are  very  few  boilers  which  do  not 
prime  more  or  less,  and  the  quantity  of  water  passed 
off  in  this  way  is  quite  considerable. 

Qnes.  In  view  of  these  facts,  can  there  be  any  accurate 
results  obtained  in  boiler  tests  ? 

Ans.  Unless  the  amount  of  water  passed  over 
with  the  steam  by  priming  or  foaming,  when  work- 
ing under  pressure,  can  be  accurately  ascertained, 
the  evaporative  results  are  not  to  be  relied  upon, 
however  careful  in  other  respects  the  trial  may  have 
been  conducted. 

Qnes.    Is  the  intensity  of  boiling  itself  constant  ? 

Ans.  It  is  not,  as  the  heat  is  ever  varying  during 
the  intervals  between  firing,  and  the  difference  in 
height  is  thus  dependant  and  changeable. 

(Jues.  What  is  the  ordinary  shop  rule  for  estimating  the 
horse  power  of  the  horizontal  tubular  boiler  ? 

Ans.  It  is  customary  to  consider  fifteen  square 
feet  when  exposed  to  the  heat  as  being  a  horse 
power,  and  it  is  figured  by  the  following  : 

Rule  for  Estimating  the  Horse  Power  of  Horizon- 
tal Tubular  Steam  Boilers. 

Find  the  square  feet  of  heating  surface  of  the  shell,  heads 
and  tubes,  and  divide  by  15  :  the  answer  is  the  nominal  horse 
power. 


ICE  MAKING  AND   REFRIGERATION.  141 


ICE  MAKING  AND  REFRIGERATION. 


The  connection  between  steam  engineering  and  refrigera- 
tion is  equally  intimate  as  that  which  exists  between  engi- 
neering and  electricity. 

Both  refrigeration  and  electricity  in  their  practical  appli- 
cation to  the  service  of  mankind  demand  the  highest 
engineering  skill,  and  it  goes  without  saying  that  the  engineer 
who  is  an  expert  in  either  of  these  widening  lines  of  progress 
will  receive  comparatively  the  highest  pecuniary  return  for 
his  service. 

That  buildings  will  be  soon  cooled  and  ventilated  in  an 
artificial  manner  is  assured  by  the  high  efficiency  now 
attained  by  mechanical  refrigerating  machines  ;  some  modi- 
fication of  the  methods  now  employed  in  cold  storage  houses 
will  be  adopted  for  buildings,  and  as  steam  will  be  the 
actuating  force,  engineers  must  necessarily  be  employed  in 
the  care  and  operation  of  the  machinery.  This  makes  it 
desirable  that  the  engineer  should  become  as  thoroughly 
posted  as  possible,  regarding  the  principles  and  operation  of 
the  yarious  mechanical  refrigerating  systems  now  in  use,  as 
well  as  those  which  will  hereafter  be  developed,  and  he  will 
find  it  greatly  to  his  advantage  to  do  so. 

The  principles  governing  artificial  refrigeration  are  simple 
and  are  becoming  familiar  to  many  engineers,  yet  many 


ICE  MAKING  AND  REFRIGERATION. 


engineers  understand  the  practical  workings  of  the  machines 
better  than  they  do  the  principles  upon  which  they  operate— 
in  view  of  the  large  future  opening  to  this  comparatively 
new  industry  it  were  well  to  unite  the  two. 

A  few  easy  definitions  at  the  introduction  of  the  subject 
may  make  the  path  of  instruction  plainer. 

A  refrigerant  is  anything  which  abates  the  sensation  of 
heat,  or  cools. 

To  refrigerate  is  to  cool  ;  to  make  cold  ;  to  allay  the  heat 
of  — 

A  refrigerating  -machine  is  a  machine  for  the  artificial 
production  of  cold. 

Refrigeration  is  specifically  the  operation  of  cooling  various 
substances  by  artificial  processes,  and 

Chemical  refrigeration  is  effected  by  the  use  of  freezing 
mixtures,  which  have  the  property  of  producing  a  sufficient 
degree  of  cold  to  freeze  liquids. 

Mechanical  Refrigeration,  in  its  strictest  sense,  is  the  con- 
version of  heat  into  work  by  the  expansion  of  a  volume  of 
gas  or  vapor,  which  performs  work  during  the  act  of  expan- 
sion ;  in  a  broader  sense,  it  is  a  process  of  refrigeration  in 
which  the  cycle  of  heat  changes  is  only  partly  produced  by 
mechanical  action,  the  mechanical  part  of  the  process  being 
wholly  confined  to  compressing  the  gas  or  vapor  while 
liquifying  it  under  the  action  of  cold  and  pressure. 

Every  refrigerating  apparatus  consists  of  three  parts,  viz.  : 
1.  The  power  (an  engine),  and  gas  (ammonia)  pumps  which 
compress  the  gas  to  a  liquifying  pressure. 


QUESTIONS  AND  ANSWERS.  143 

2.  A  condenser  in  which  the  gas  is  cooled  and  changed  to 
a  liquid. 

3.  A  system  of  evaporating  coils,   in  which  the  liquid 
ammonia  is  expanded  into  a  gaseous  state  and  thus  cools  the 
surrounding  space  by  the  absorption  of  heat. 

The  refrigerating  agent  better  than  any  known  substance 
which  has  proved  most  advantageous  is  ammonia.  This 
chemical  boils  at  40°  below  zero — as  water  boils  at  212°  above 
zero — thus  assuring  a  low  temperature  without  resorting  to 
very  low  pressures. 


Questions   and  Answers  Relating    to    Refrig- 
eration. 

Ques.    What  is  anhydrous  ammonia  ? 

Ans.  The  word  anhydrous  means  "  free  from 
water":  ammonia  unmixed  with  water  is  sometimes 
called  dry  ammonia. 

Ques.  What  are  the  advantages  of  ammonia  over  other 
fluids  for  refrigeration  ? 

Ans.  Its  great  stability,  its  non-inflamibility  and 
non-explosiveness  ;  it  does  not  have  the  slightest 
effect  on  iron  and  steel,  even  when  mixed  with  water, 
so  that  the  machinery  and  piping  which  convey  and 
circulate  it  are  never  in  the  least  degree  corroded. 

Ques.    What  is  the  standard  of  cold  production  ? 

Ans.  It  is  the  weight  of  the  gas  circulated  through 
the  system  and  not  the  volume  of  gas. 


144  ENGINEERS'  EXAMINATIONS. 

Qnes.  How  much  cold  can  be  produced  from  a  pound  of 
coal? 

Ans.  Numerous  tests  have  shown  that  with  a 
fairly  constructed  refrigerating  machine  a  melting 
capacity  equal  to  that  of  16  to  48  Ibs.  of  ice  can  be 
obtained  from  a  Ib.  of  coal.* 

Ques.    What  is  the  Brine  system  of  refrigeration  ? 

Ans.  In  the  Brine  system  one  or  more  tanks  of 
salt  water  are  used,  in  which  the  evaporating  coils 
are  submerged,  and  the  liquid  ammonia,  allowed  to 
expand  within  the  coils,  assumes  its  original  gaseous 
condition  and  in  doing  so  absorbs  the  heat  from  the 
surrounding  brine,  reducing  it  to  any  reauired  tem- 
perature. 

Ques.    In  ice  making  how  is  the  brine  tank  arranged  ? 

Ans.  It  is  arranged  to  receive  galvanized  sheet 
iron  cans  containing  fresh  water,  which  remain  in 
the  brine  until  their  contents  are  frozen  into  solid 
blocks  of  ice. 

Ques.    What  is  the  direct  expansion  system  ? 

Ans.  In  the  direct  expansion  system  the  ammonia 
expands  directly  in  coils  placed  in  the  rooms  to  be 
cooled. 

Ques.  Which  system  (brine  or  direct  expansion)  is  mostly 
used,  and  why  ? 

Ans.  The  brine  system,  because  the  brine  tanks 
afford  a  considerable  reservoir  of  cold  which  may  be 


*  The  wide  difference  given  is  shown  by  the  tests  and  it  will  be 
found  that  the  capacity  varies  with  the  conditions. 


QUESTIONS  AND  ANSWERS.  145 

drawn  upon  in  an  emergency;  another  strong  reason 
is  that  there  is  less  risk  of  loss  in  the  cooling  rooms 
from  escaped  ammonia  from  leaking  pipes;  still 
another  reason  for  preferring  the  brine  system  is 
because  the  whole  system  of  the  ammonia  gas 
circulation  is  confined  to  one  room  or  department, 
and  directly  under  the  control  of  the  engineer. 

(Jues.  In  the  brine  system  how  is  the  brine  circulated  ? 
Describe  the  process. 

Ans.  It  is  accomplished  by  a  special  pump 
described  as  the  brine  circulating  pump,  which 
forces  it  through  the  pipes  arranged  in  the  rooms  to 
be  cooled,  from  which  it  returns  to  the  tank  to  be 
re-cooled  and  continually  used  over  again,  through 
an  endless  round  of  cooling  and  warming. 

Ques.  Is  the  brine  circulation  quite  independent  of  the  gas 
circulation  ? 

Ans.  Yes,  the  only  spot  they  come  in  contact  is  in 
the  brine  tank;  here  the  cold  ammonia  gas  extracts 
the  heat  from  the  brine  as  it  flows  through  the  tank; 
the  two  circulation  systems  do  not  come  in  nearer 
contact  than  that. 

(Jues.    How  is  the  cooling  effected  in  the  direct  expansion 

system  ? 

Ans.  In  the  direct  expansion  system  the  ammonia 
expands  directly  in  coils  placed  in  the  rooms  to  be 
cooled,  the  pipes  being  stronger,  but  in  other  respects 
similar  to  those  used  in  the  brine  circulation ;  in 
this  system  the  brine  pump  is  omitted. 


146  ENGINEERS'  EXAMINATIONS. 

(Jues.  What  is  the  difference  between  a  submerged  con- 
denser and  an  open  air  condenser  ? 

Ans.  In  one  plan  the  system  of  pipes  is  sunk  in 
a  tank  containing  water  and  in  the  other  the  pipes 
are  exposed  to  the  air  and  water  sprinkled  over 
them. 

Ques.  In  either  plan  or  method  what  is  the  common 
result  ? 

Ans.  The  water  extracts  the  heat  from  the  pipes, 
being  under  the  requisite  pressure  the  ammonia  is 
cooled  to  the  temperature  of  the  condensing  water, 
and  becoming  liquified,  is  ready  for  use. 

(Jues.  What  other  principal  system  of  refrigeration  is  in 
use  ?  Describe  it. 

Ans.  The  absorption  system.  This  consists  in 
a  ditierent  arrangement  of  i,  the  power,  2,  the  con- 
denser, and  3,  the  evaporating  coils,  as  mentioned 
on  page  142.* 

Qties.  What  are  the  parts  of  the  absorption  system  spec- 
ially called  ? 

Ans.  i.  The  Generator.  2.  The  Ammonia  Pump. 
3.  The  Absorber.  4.  The  Condensing  Tank.  5. 
Weak  Liquor  Tank.  6.  The  Equalizer.  7.  The 
Freezing  Tank.  8.  The  Cooling  Tank.  9.  Receiver 
for  Ammonia. 


*  These  are  mentioned  on  page  142  as  essential  to  all  systems  01 
refrigeration. 


QUESTIONS  Aim  ANSWERS.  147 

Ques.  What  refrigerant  is  mostly  used  in  the  absorption 
system  ? 

Ans.  Ammonia  largely  reduced  and  mixed  with 
water  so  that  it  is  26  per  cent,  strong — called  prop- 
erly, aqua-ammonia. 

(Jues.  Upon  what  chemical  law  is  the  absorption  system 
based  ? 

Ans.  Upon  that  which  allows  ammonia  to  boil 
into  gas  at  40  degrees  below  zero,  while  water  is 
unaffected  until  212  degrees  is  reached  ;  the  ammonia 
and  water  are  thereby  capable  of  being  separated 
and  thus  made  to  perform  continuous  work. 

Ques.    What  is  the  expansion  valve  ? 

Ans.  It  is  that  which  controls  the  supply  of 
ammonia  to  the  evaporating  coils 

Ques.  What  advantage  is  to  be  gained  by  the  use  of  the 
device  called  "the  agitator  "  ? 

Ans.  Its  use  is  to  secure  uniform  freezing,  which 
is  accomplished  by  continually  circulating  and  agi- 
tating the  bath — this  is  sometimes  done  by  the  use 
of  a  centrifugal  pump,  which  draws  the  brine  from 
one  end  at  the  bottom  and  discharging  in  the  other 
end  at  the  top. 

(fues.  "What  is  the  cycle  or  circle  of  the  ammonia  in  its 
two  forms  through  its  round  of  use  and  re-use  ? 

Ans.     I.  Compression.     2.  Condensation.     3   Ex 
pansion.     In  order  to  render  the  operation  continu- 


148  ms&BMaiBff  EXAMINATIONS. 

ous   these   three   are   connected   together,  the   gas 
passing  through  the  system  in  the  order  named. 

Ques.    To  what  extent  is  the  ammonia  compressed  ? 

Ans.  From  125  to  175  Ibs.  per  square  inch, 
depending  upon  the  temperature  of  the  condensing 
water  used,  either  mechanically  or  otherwise,  in 
order  to  prepare  it  for  the  second  operation-express- 
ed more  plainly,  "  heat  is  squeezed  out  of  the  gas. 

Qnes.    How  about  the  condensation  ? 

Ans.  The  heat  developed  or  "squeezed  out"  in 
the  compression  is  withdrawn  from  the  compressed 
gas  by  forcing  it  through  coils  of  pipe  while  they  are 
in  contact  with  cold  water — the  heat  being  trans- 
ferred to  the  water  surrounding  the  coils.* 

Ques.  Of  what  does  the  expansion  side  consist  and  what 
is  its  operation  ? 

Ans.  The  expansion  side  generally  consists  of 
coils  of  pipe,  in  which  the  gas  re-expands  and  per- 
forms the  refrigerating  work  ;  through  these  pipes 
the  ammonia  gas  is  drawn  by  the  pumps  at  a  press- 
ure varying  from  10  to  30  Ibs.  above  that  of  the 
atmosphere. 

Ques.    Where  do  the  "  parts  "  meet  3 

Ans.  The  liquified  gas  is  allowed  to  flow  to  a 
stop-cock  having  a  minute  opening  which  separates 
the  compression  from  the  expansion  sides. 

*  When  tliis  point  is  reached  the  gas  is  ready  to  assume  the  liquid 
condition,  and  in  so  doing,  is  ready  to  give  off  additional  heat  to  the 
surrounding  water. 


QUESTIONS  AND  ANSWERS.  149 

Ques.    What  are  air  machines  ? 

Ans.  Machines  that  use  air  instead  of  ammonia; 
cold  can  be  generated  by  the  expansion  of  air  ;  air 
becomes  heated  under  compression  and  will  cool 
down  again  during  compression.  Air  machines  are 
generally  used  on  ship-board  where  machines  of 
comparatively  small  capacities  are  needed. 

Ques.    What  are  the  objections  to  air  machines  ? 

Ans.  Their  large  coal  consumption,  which  is 
eight  to  ten  times  that  of  good  ammonia-compress- 
ion machines — besides  this  the  compressing-pumps 
are  very  large,  the  friction  to  operate  them  is  great 
and  the  loss  by  leakage  around  the  piston  becomes 
considerable  in  course  of  time. 

Ques.    What  is  a  double-acting  compressor  ? 
Ans.     One  which  handles  the   gas  on  both   the 
upward  and  downward  stroke. 

Ques.    What  are  its  advantages  ? 

Ans.  The  friction  will  be  the  same  for  all  the 
working  parts,  while  double  the  work  is  being 
effected. 

Ques.  What  is  the  greatest  trouble  to  be  overcome  in 
refrigerating  machinery  if 

Ans.     Leakage. 

Ques.  What  should  be  one  of  the  first  rules  as  to  the 
machinery  and  appliances  ? 

Ans.  They  should  be  kept  clean  and  in  good 
order ;  means  should  be  provided  for  cleaning  the 
entire  distilling  system  by  steam. 


160  a&Af  Aim  wottz. 


HEAT  AND  WORK. 


Without,  heat  there  would  be  no  steam  engine  nor  steam 
boiler,  neither  engineer  or  fireman. 

The  services  of  the  engineer  are  chiefly  devoted  to  chang- 
ing heat  into  work ;  the  heat  which  is  carried  to  the  engine 
in  the  steam  is  either  transformed  into  useful  work,  or  it 
passes  away  to  waste  in  various  ways,  and  the  sum  of  the 
heat  usefully  employed  plus  the  heat  which  is  wasted  always 
equals  exactly  the  heat  which  was  applied. 

This  is  owing  to  a  fundamental  principle  hi  nature  that, 
just  as  matter  can  neither  be  created  nor  destroyed,  though 
it  may  be  made  to  assume  different  forms,  visible  or  invisible, 
so  energy,  whether  heat  energy  or  any  other,  cannot  be 
destroyed.  It  may  take  a  variety  of  different  forms,  but  the 
sum  total  of  the  energy  remains  the  same.  This  principle  is 
called  the  principle  of  the  "conservation  of  energy." 

The  temperature  of  a  body  indicates  how  hot  or  how  cold 
the  body  is. 

We  must  not  fail,  however,  to  distinguish  the  temperature 
of  a  body  from  the  quantity  of  heat  in  a  body.  Thus,  if  a 
cup  of  water  be  dipped  out  of  a  pailful  of  water,  the  temper- 
ature of  the  water  is  the  same  throughout,  but  the  quantity  of 
heat  varies  as  the  weight  of  water  in  each  vessel 


SEAT  Atib  WORK:.  151 

Before  quantities  of  heat  can  be  measured  we  must  have  a 
unit  of  heat,  just  as  we  require  a  unit  of  length.  Namely  ; 
the  inch  or  foot  in  order  to  measure  distance,  or  the  pound 
or  ton  in  order  to  measure  weight. 

The  unit  of  heat  is  the  amount  of  heat  necessary  to  raise 
the  temperature  of  one  pound  of  water  one  degree  Fahren- 
heit when  at  a  normal  temperature. 

Heat  is  transferable  from  one  body  to  another,  that  is,  one 
body  can  heat  another  by  becoming  less  hot  itself ;  thus,  the 
furnace  heat  is  transferred  to  the  boiler  plates,  thence  to  the 
water  and  steam,  and  finally  to  the  piston,  in  the  driving  of 
which  heat  is  changed  into  work. 

The  natural  condition  of  heat  is  a  condition  of  energy,  that 
is  of  a  condition  to  effect  changes — of  coal  into  gas,  of  water 
into  steam — and  steam  into  work. 

Ques.    What  is  the  mechanical  equivalent  of  heat  ? 

Ans.  The  amount  of  heat  necessary  to  raise  i 
Ib.  water  from  or  near  its  freezing  point  (32°)  one 
degree,  is  equivalent  to  the  mechanical  power  which 
will  raise  772  Ibs.  through  a  height  of  one  foot. 

Qnes.    How  can  we  express  units  of  heat  as  units  of  work? 
Ans.     Multiply  the  units  of  heat  by  772. 

Ques.  How  does  this  question  of  heat  and  work  affect  the 
engineer  ? 

Ans.  The  whole  business  of  the  engineer  is  the 
superintendence  of  machines  by  means  of  which  the 
conversion  of  heat  may  be  carried  out. 


152  HEAT  AND  WORK. 

Ques.    What  is  a  thermometer  for  and  how  does  it  act  ? 

Ans.  Thermometers  are  used  to  indicate  tem- 
perature, and  they  do  so  by  the  rise  and  fall  of  a 
little  column  of  mercury  enclosed  in  a  tube  of  very 
fine  bore,  and  having  a  small  bulb  at  the  bottom 
containing  a  store  of  mercury. 

Ques.    How  does  this  show  change  of  heat  or  temperature? 

Ans.  If  the  thermometer  be  warmed  by  any 
means,  the  mercury  expands  and  tends  to  occupy  a 
larger  volume,  and  the  column  therefore  rises  in  the 
stem  of  the  tube  ;  or,  if  the  thermometer  be  cooled, 
the  mercury  will  contract  or  diminish  in  volume, 
and  the  column  will  shorten  or  fall.  A  graduated 
numbered  scale  is  affixed  and  the  smallest  change  in 
temperature  shown  by  the  movement  of  the  surface 
of  the  column  is  thus  very  easily  detected. 

Ques.  How  is  the  thermometer  scale  divided  or  grad- 
uated? 

Ans.  The  instrument  is  placed  in  melting  ice, 
and  the  point  to  which  the  mercury  falls  is  marked 
the  freezing  point.  It  is  then  put  in  boiling  water 
exposed  to  the  air  and  the  point  to  which  the  mer- 
cury column  rises  is  marked  the  boiling  point.  The 
distance  between  these  two  points  on  the  most  com- 
monly used  thermometer,  the  Fahrenheit,  is  divided 
into  1 80  equal  parts  or  degrees. 

On  the  Centigrade  thermometer  the  distance  be- 
tween these  two  marks  is  divided  intp  100  equal 
spaces  or  degrees — the  word  Centigrade  is  derived 


HEAT  AND  WORK.  153 

from  the  two  words  meaning  a  grading  by  the  hun- 
dred. 

In  the  Reaumur  scale,  the  same  distance  is  divided 
into  80  degrees. 

(Jues.    What  is  the  position  of  zero  on  these  scales  ? 

Ans.  The  last  two  make  the  freezing  point  zero, 
while  the  Fahrenheit  makes  the  freezing  poi^t  32° 
and  thus  the  zero  is  i8o°+32°,  or  212°  below  boiling 
point,  and  temperatures  are  measured  from  zero  up 
and  down  the  scale. 

(Jues.    "What  is  meant  by  the  term  "energy  "  ? 

Ans.  It  may  be  defined  as  the  power  of  doing 
work.  When  heat  is  applied  to  water  it  confers 
upon  the  steam  which  is  produced  the  power  of 
doing  work,  such  as  driving  the  piston  from  one  end 
of  the  cylinder  to  the  other,  against  a  resistance. 

(Jues.    What  is  specific  heat  ? 

Ans.  It  is  the  heat  required  to  raise  the  temper- 
ature of  a  substance  one  degree,  as  compared  with 
the  heat  necessary  to  raise  the  temperature  of  an 
equal  weight  of  water  one  degree. 

The  specific  heat  of  bodies  varies  very  considerably,  as  will  be  seen 
from  the  following  table : 

Table  of  Specific  Heat. 
Water  =1.000 


Cast  Iron . 
Steel 

Wrought  Iron 
Copper 
Bismuth  . 
Lead 


=0.130 
=0.118 
=0.113 
=0.100 
=0.031 
=0.031 


Mercury  •••••••    =0.033 

Coal          .  .  =0241 


154  MEAStT&ES  Aim  WEIGHTS. 


MEASURES  AND  WEIGHTS. 


A  large  proportion  of  time  is  taken  up  in  counting,  in 
measuring  and  in  weighing,  and  an  engineer's  success  in  the 
path  of  advancement  is  largely  influenced  by  his  readiness  in 
these. 

To  avoid  disputes  there  needs  to  be  a  certain  well  agreed 
upon  standard,  both  of  weights  and  measures,  by  which 
all  will  agree  to  be  governed. 

This  agreed  standard  for  each  operation  is  called  the  unit. 

Ques.    What  is  the  unit  or  measure  of  time  ? 

Ans.     A  minute. 

(Jues.    What  is  the  unit  of  arithmetical  calculations  ? 

Ans.     The  figure  (i)  one; 

(Jues.     What  is  the  unit  of  pressure  ? 

Ans.  The  pressure  of  the  atmosphere  at  the  level 
of  the  sea.  14-^  Ibs.  to  the  square  inch. 

Ques.    What  is  the  unit  of  work  ? 

Ans.  The  foot-pound,  which  is  the  force  required 
to  lift  one  pound  one  foot  high.  33,000  of  these 
make  one  horse-power  when  executed  in  the  unit  of 
time  (one  minute). 

Ques.    What  is  the  unit  of  heat  ? 

Ans.  It  is  the  heat  required  to  raise  one  pound 
of  water  one  degree — or  say,  one  pound  of  water 
from  32°  to  33°. 


STEAM  HEATING  AND  VENTILATION.  155 


STEAM   HEATING   AND    VENTILATION. 


No  small  proportion  of  engineers'  positions  are  retained, 
after  being  secured,  by  a  practical  familiarity  with  the  care 
and  management  of  the  heating  and  ventilating  apparatus ; 
it  is  true  that  nearly  always  this  apparatus  is  furnished;  as 
to  plan  and  detail,  by  the  architect,  yet  tne  engineer  must 
operate  it  to  the  satisfaction  of  the  owner  of  the  steam  plant, 
or  lose  his  situation 

Hence  it  follows  that  no  engineer  will  be  granted  a  license 
to  run  a  steam  plant,  where  there  is  an  extensive  system  of 
heating,  unless  he  shows  by  his  answers  that  he  is  capable  of 
its  management  and  understands,  somewhat,  the  principles 
upon  which  it  acts. 

A  system  of  heating  and  ventilation  should,  in  the  first 
place,  be  simple,  so  that  the  average  engineer  shall  be  compe- 
tent to  operate  it.  It  should  be  of  sufficient  capacity  to  do 
the  heating  required  for  all  the  space,  and  it  should  be  safe, 
durable  and  economical. 

In  planning  and  in  the  management  of  the  apparatus,  both 
the  heating  and  ventilation  should  be  considered  as  one — they 
are  inseparable  and  together  form  a  complete  whole  ;  the 
apparatus  should  warm  the  air  in  an  enclosed  space  to  a 
temperature  conducive  to  comfort  and  health,  and  supply  a 
volume  of  air  sufficient  to  maintain  a  sanitary  standard  of 
purity;  both  conditions — heating  and  ventilation — must  be 


156  ENGINEERS'    EXAMINATIONS. 

controllable  and  constant,  with  the  air  deliveries  so  made  that 
no  complaint  can  be  found  with  the  engineer  in-charge. 

In  heating  and  ventilating,  the  natural  laws  which  govern 
must  be  regarded,  otherwise  all  applications  will  be  experi- 
mental, thus  : 

1.  Air  occupies  space  the  same  as  solids  and  liquids,  but 
because  it  is  invisible  it  is  not  so  regarded. 

2.  Cold  air  falls  because  of  its  density  and  heated  air 
rises  because  of  its  rarity. 

3.  A  given  volume  of  air  occupies  a  given  space  ;  a  like 
volume  cannot  occupy  the  same  space  at  the  same  time. 

4.  A  volume  of  air  can  be  delivered  into  a  room  only 
equal  to  the  quantity  displaced  therefrom;  when  a  space  is 
full  it  can  hold  no  more. 

Ventilation  is  a  substitution  of  fresh  air  for  foul ;  it  should 
be  a  gradual,  constant  and  complete  changing  of  the  air  in  a 
room  or  structure. 

The  piping  of  a  mill  or  factory  or  workshop  was,  compara- 
tively, a  few  years  ago,  an  easy  task.  To-day  high  buildings, 
with  hundreds  of  business  offices,  government  buildings  with 
elaborate  equipment  and  furniture,  art  institutes  and 
museums  with  treasures  and  relics,  mansions  and  cottages, 
are  being  warmed  by  special  systems  studied  out  by  the 
mechanical  engineer  and  master  steam-fitter. 

The  systems  are  becoming  intricate ;  they  require  drawings, 
planning,  accurate  measurements  and  calculations  on  areas 
and  capacities,  mechanical  knowledge  of  steam  and  water,  of 
pipes,  furnaces,  boilers,  valves,  fittings  and  those  other 
adjuncts  which  have  become  necessary  in  the  extensive  use 


QUESTIONS  AND  ANSWERS.  157 

of  steam  and  hot  water.  In  short,  there  is  a  great  deal  to  be 
learned  concerning  present  methods,  and  a  great  deal  more 
to  be  learned  in  the  future,  as  experience,  invention  and 
improvement  will  show. 

It  is,  therefore,  tune  for  this  branch  of  business— steam 
and  hot  water  heating — to  be  recognized  as  one  worthy  of 
attention,  investigation  and  study. 


Questions  and  Answers  Relating  to  Heating 
and  Yentilation. 


Ques.  What  is  a  very  important  principle  to  be  observed 
in  arranging  a  system  of  piping  ? 

Ans.  They  should  be  so  designed  that  there  is  a 
gradual  slant  from  feed  to  return,  with  no  air  or 
water  "  pockets  "  and  nothing  to  be  in  the  way  of  a 
thorough  circulation. 

Ques.  How  should  the  fire  surface  of  a  boiler  be  propor- 
tioned to  the  quantity  of  pipe  to  be  heated  ? 

Ans.  The  extent  of  surface  which  a  boiler  should 
expose  to  the  fire  should  be  proportional  to  the 
quantity  of  pipe  to  be  heated,  and  a  small  apparatus 
should  have  more  surface  of  boiler  in  proportion  to 
length  of  pipe  than  a  larger  one,  as  the  fire  is  less 
intense  and  burns  to  less  advantage  in  a  small  fur- 
nace than  in  a  large  one.  It  is  more  economical  to 


158  ENGINEERS'  EXAMINATIONS. 

work  with  larger  surface  of  boiler  at  moderate  heat 
than  to  keep  the  boiler  at  its  maximum  temperature. 

(Jues.  In  taking  charge  of  a  new  plant,  what  is  the  first 
thing  to  be  done  by  the  engineer  ? 

Ans.  To  ascertain  the  exact  course,  size  and 
operation  of  the  steam,  water,  drain  and  other  pipes. 

Ques.     Why  is  it  necessary  to  do  this  so  soon  ? 

Ans.  Because  the  boilers  cannot  be  supplied 
with  water  even,  nor  blown  off  without  the  pipes 
being  in  order,  nor  steam  taken  to  the  engine  nor 
distributed  in  a  heating  system  without  proper  con- 
nections. Besides,  it  is  well  to  do  the  most  difficult 
thing  first — the  piping,  being  largely  out  of  sight,  is 
most  difficult  to  inspect — more  so  than  the  engine, 
boilers  or  pumps. 

Ques.  Name  some  of  the  essentials  to  an  efficient  system 
of  piping  ? 

Ans.  Pipes  and  valves  should  be  of  sufficient  size 
to  carry  the  full  pressure  of  the  boiler  to  the  engine; 
elbows  with  a  long  turn  are  best,  and  T's  are  to  be 
avoided,  if  possible.  Pipes  of  proper  size  and  easy 
bends  are  essential  to  economy. 

(Jues.  What  other  matter  relating  to  the  piping  is  essential 
to  economy  ? 

Ans.  The  covering  of  all  pipes  by  some  good 
non-conducting  substance,  as  condensation  in  the 
pipes  when  uncovered  or  partly  covered  increases 
greatly  the  cylinder  condensation.  This  covering  is 


QUESTIONS  AND  ANSWERS.  159 

as  important  in  warm  as  in  cold  weather,  as  steam 
80  to  100  Ibs.  pressure  has  a  temperature  of  325  to 
342  degrees  of  heat. 

Ques.  What  is  well  to  be  known  by  an  engineer  relating 
to  steam  fitting  and  piping  ? 

Ans.  It  is  almost  a  necessity  to  know  the  names 
and  uses  of  pipe  fitter's  tools,  to  be  familiar  with  the 
different  fittings  and  styles  of  valves,  sizes,  ete. 

Ques.  What  are  some  of  the  fittings  ?  Name  a  few  of 
them. 

Ans.  Gaskets,  nipples,  steam  and  water  unions, 
couplings,  ells,  lock  nuts,  off-setts,  coils,  radiators, 
steam  traps,  headers. 

Ques.    What  is  the  very  best  non-conductor  of  heat  ? 

Ans.  Confined  air — hence  the  best  composition 
for  steam  pipes  is  that  which  has  the  largest  quan- 
tity of  confined  air  mixed  with  the  material  of  which 
it  is  composed. 

Ques.  In  pipe  covering  what  two  dangers  must  be  guarded 
against  ? 

Ans.  The  danger  of  fire,  and  second,  that  there 
are  no  currents  of  air  formed  between  the  pipe  and 
the  covering. 

Ques.    What  is  the  latest  idea  hi  regard  to  ventilation  ? 

Ans.  That  the  best  results  are  only  to  be  had  by 
a  mechanical  system,  extracting  the  air  and  replac- 
ing it  by  fresh  supplies — hence  the  increasing  use  of 
exhaust  fans  and  blowers  driven  by  various  motors. 


160  $BE  SMOKE  PROBLEM. 


THE   SMOKE   PROBLEM. 


Much  vexatious  litigation  has  been  caused  by  the  "  smoke 
nuisance  ",  so  denominated  in  the  ordinances  passed  by  many 
cities  ;  there  has  been  a  lively  controversy  between  the  offi- 
cials and  steam-users  as  to,  first,  the  possibility  and,  second, 
the  practicability  of  preventing  smoke  from  issuing  from  the 
tops  of  the  chimneys  of  steam  plants.  Many  proprietors 
have  been  called  to  the  bar  of  justice  and  fined  for  the 
offence,  and  not  a  few  engineers  have  been  threatened  with 
arrest ;  at  tunes  both  engineers  and  owners  have  been  sum- 
moned to  plead  guilty  or  not  guilty  to  the  crime  of  smoke 
production. 

That  smoke  can  be  absolutely  prevented  is  proved  by  the 
operations  of  gas  works,  which  yearly  converts  into  gas, 
coke,  tar,  etc.,  millions  of  tons  of  bituminous  coal  without 
smoke. 

The  smokeless  combustion  of  powdered  coal,  which  has 
recently  become  an  important  fact  in  Europe,  is  greatly 
facilitated  by  the  adoption  of  a  new  automatic  mechanism 
and  other  arrangements.  The  fuel,  instead  of  being  intro- 
duced in  the  ordinary  manner,  is  first  ground  to  a  powder, 
and,  in  place  of  the  ordinary  boiler  fire-box,  there  is  a  com- 
bustion chamber  in  the  form  of  a  closed  furnace  lined  with 
firebrick,  and  having  an  injector  similar  in  construction  to 
those  used  in  oil  burning  furnaces.  This  chamber  has  two 
openings,  one  on  the  centre  line  and  in  the  place  of  the  usual 


THE  SMOKE  PROBLEM.  161 

furnace  fire  door  and  the  other  on  the  opposite  side.  The 
orifice  of  the  nozzle  is  placed  in  the  latter  aperture  and 
throws  a  constant  stream  of  fuel  into  the  chamber,  the 
nozzle  being  so  located  that  it  scatters  the  powder  throughout 
the  whole  space  of  the  firebox  ;  when  the  powder  is  once 
ignited,  which  is  very  readily  done  by  first  raising  the  lining 
to  a  high  temperature  by  an  open  fire,  the  combustion  con 
tinues  in  an  intense  and  regular  manner  under  the  action  of 
the  current  of  air  which  carries  it  in.  This  current  is  regu- 
lated by  the  amount  of  powder  required  for  the  production  of 
the  heat  led  off  to  the  boiler  and  the  evaporation  of  the 
weight  of  steam  demanded. 

It  may  thus  be  seen  that  the  question  is  not  one  of  possi- 
bility but  of  practicability  or  economy ;  it  being  allowed  that 
smoke  prevention  cannot  be  economically  effected,  then  the 

English  towns  are  more  troubled  by  the  smoke  nuisance  than  any 
of  those  of  our  own  country.  The  absolute  abatement  of  the  smoke 
being  economically  impossible,  the  cities  have  adopted  ordinances  to 
control  and  mimimize  the  nuisance.  Thus  Manchester,  for  example, 
has  a  city  law  which  permits  of  the  continuous  emission  of  black 
smoke  from  any  factory  for  one  minute  each  half  hour.  Oldham 
allows  nine  minutes  per  hour.  St.  Helens,  Newcastle-on-Tyne  and 
Leeds,  five  minutes.  At  Birmingham  the  inspectors  watch  the  chim- 
ney for  an  hour ;  they  report  the  way  in  which  the  smoke  is  emitted, 
whether  continuous  or  at  intervals.  For  a  first  offense,  or  where  a 
long  time  has  elapsed  between  offenses,  letters  of  caution  are  sent  out. 
Sheffield  allows  six  minutes  in  the  hour,  but  where  there  are  not  more 
than  three  steam  boilers  and  no  furnaces,  four  minutes  in  the  hour 
only.  At  Stoke-on-Trent  if  black  smoke  is  emitted  for  a  longer  period 
than  fifteen  minutes,  proceedings  are  taken.  Bolton  allows  two  and  a 
half  minutes  in  the  half  hour.  In  this  connection  it  may  be  of  inter- 
est to  state  that  the  3'anchester  Association  has  caused  1827  half- 
hourly  observations  to  be  made  of  various  chimneys  of  the  members, 
and  the  result  of  these  observations  showed  that  black  smoke  issued 
for  3224  minutes,  an  average  of  one  minute  forty-six  seconds  per  half 
hour. 


162  THE  SMOKE  PROBLEM. 

problem  is  as  to  a  medium  effect.  Attention  is  called  to  the 
foot  note  regarding  the  practice  obtained  in  England  in 
dealing  with  the  question. 

"Human  nature  has  not,"  said  recently  a  distinguished 
lecturer,  "is  not,  nor  will  it  ever,  be  able  to  dole  out  the 
exact  equivalent  of  air  necessary  for  the  complete  consump- 
tion of  each  fresh  charge  of  coals  on  the  furnace  grate." 
One  of  the  reasons  given  was,  "that  coals  differed  so  much 
in  the  quantity  of  their  constituents  as  to  make  the  above 
impossible." 

In  an  investigation  made  by  the  lecturer,  data  was  collec- 
ted of  the  number  of  tons  of  coal  consumed  in  a  given  time 
by  thirteen  puddling  furnaces,  and  also  of  the  color  of  the 
smoke  emitted  from  the  same.  About  30,000  cubic  feet  of 
smoke  gases  were  emitted  every  seventy  seconds,  of  which 
the  speaker  declared  that,  "he  was  willing  to  forfeit  any 
reasonable  sum  of  money,  if  any  one  could  prove  that  there 
was  more  than  one  part  by  weight  of  unburnt  fuel  in  2,680 
parts,  owing  to  rarefaction  and  the  smoke  on  the  average 
being  only  of  a  light  brown  color. " 

One  point  made  is  not  without  its  pertinence  in  the  present 
crusade  against  the  smoke  nuisance,  and  it  is  given  as  stated 
regarding  some  unreasonable  prosecutions  made  of  offenders  : 
"If  people  more  generally  knew  what  the  composition  of 
smoke  was,  manufacturers  would  not  in  many  cases  be  per- 
secuted and  prosecuted  as  at  present,  and  authorities  would 
exercise  their  discretionary  powers  in  a  more  sensible  and 
lenient  manner. "  It  need  hardly  be  said  that  in  very  many 
instances  of  offense  this  criticism  is  not  without  its  \veight. 


QUESTIONS  AND  ANSWERS.  163 


Questions  and  Answers  Relating  to  the 
Prevention  of  Smoke. 

Ques.  What  is  the  first  requisite  in  the  solution  of  the 
smoke  problem  ? 

Ans.  Its  formation  should  be  prevented  at  the 
start,  as  the  after-combustion  or  burning  of  smoke  is 
almost  impossible  and  quite  the  reverse  of  econom- 
ical. 

Ques.  Give  the  generally  accepted  practice  in  prevention 
of  smoke. 

Ans.  A  high  furnace  temperature  is  most  essen- 
tial and  this  is  best  secured  by  a  good  draft;  second, 
ample  space  in  the  furnace  or  combustion  chamber 
for  the  mixture  of  the  products  of  combustion 
(gases),  mixed  with,  third,  a  due  proportion  of  air  ; 
this  must  be  supplied  in  some  common  sense  manner, 
either  through  perforations  in  the  furnace  door  or 
through  minute  openings  in  the  bridge  or  side  walls. 

Ques.    Where  must  the  air  be  otherwise  supplied  ? 
Ans.     Through  the  grate  bars. 

(Jues.  What  proportion  of  air  space  should  there  be 
between  the  bars  ? 

Ans.  Generally  speaking,  50  per  cent.,  although 
this  amount  may  be  increased  for  large  size,  hard 
and  lump,  bituminous  coal  ;  for  pea  or  nut  coal  the 
distance  between  the  bars  must  be  less. 


164  ENGINEERS'   EXAMINATIONS. 

Qnes.  What  are  some  of  the  principal  difficulties  in  the 
way  of  smoke  prevention  ? 

Ans.  The  worst  trouble  comes  from  uneven 
chimney  draft,  and  again  the  varying  qualities  of 
coal  which  require  different  quantities  of  air-admix- 
ture. 

Ques.  Is  there  any  difference  made  in  the  quantity  of 
smoke  by  having  too  much  or  too  little  air  ? 

Ans.  Yes,  either  too  much  or  too  little  air  causes 
imperfect  combustion — hence  the  smoke. 

Ques.  If  the  exact  quantity  of  air  needed  was  supplied  to 
the  furnace,  would  there  be  any  smoke  ? 

Ans.  Not  any  to  be  observed.  It  may  be  said 
thus — with  no  air  absolutely  no  combustion  ;  with 
right  quantity — then  perfect  combustion  ;  with  too 
much  or  too  little  then — smoke. 


Computations  usually  made  of  stack  capacity  assume  the  chim- 
ney gases  to  be  of  the  same  specific  gravity  as  air.  This  is  not  true, 
as  when  combustion  is  complete  the  gases  are  really  a  mixture  of 
carbonic  acid  gas,  nitrogen  and  steam  ;  the  proportions  varying  with 
different  coals.  As  these  require  different  amounts  of  air,  the  vary- 
ing weights  of  the  gases  of  combusiion  cause  a  difference  in  the  draft 
power  of  the  same  chimney.  It  is  rare  that  just  the  proper  amount  of 
air  is  admitted,  and  there  is  a  loss  when  the  amount  is  too  little  or  too 
great.  Very  often  there  is  a  surplus  of  air,  reaching  sometimes  as 
high  as  100  per  cent. 


ARITHMETICAL  SIGNS.  165 


ARITHMETICAL  SIGNS. 


There  are  various  characters  or  marks  used  in  arithmetical 
computations,  to  denote  several  of  the  operations  and  propo- 
sitions, the  chief  of  which  are  as  follows  : 

=  Equal  to.  The  sign  of  equality  ;  as  100  cents=$l,  signi- 
fies that  100  cents  are  equal  to  one  dollar. 

—  Minus,  or  Less.  The  sign  of  subtraction  ;  as  8  — 2=6  ; 
that  is,  8,  less  2,  is  equal  to  6. 

4-  Plus,  or  More.  The  sign  of  addition  ;  as  44-5 =9  ;  that  is, 
4,  added  to  5,  is  equal  to  9. 

X  Multiplied  by.  The  sign  of  multiplication  ;  as  6x6=36  ; 
that  is,  6,  multiplied  by  6,  is  equal  to  36. 

-~-  Divided  by.  The  sign  of  division  ;  as  12-^-3  .=4  ;  that  is, 
12,  divided  by  3,  is  equal  to  4. 

.    f  The  signs  of  proportion  ;as2:4::8:16;  that  is, 
:  ^o      f      as  2  is  to  4,  so  is  8  to  16. 

7—2-}-5=10.  Shows  that  the  difference  between  7  and  2, 
added  to  5,  is  equal  to  10. 

2  added  to  a  number,  signifies  that  the  number  is  to  be 
squared ;  thus  :  62,  means  that  6  is  to  be  multiplied  by  6. 

8  added  to  a  number,  signifies  that  the  number  is  to  be 
cubed;  thus  :  53  — 5x5x5=125.  The  index,  or  power, 
is  the  number  of  times  a  number  is  to  be  multiplied  by 
itself,  and  is  shown  by  a  small  figure  placed  at  the  right 
of  the  number  to  be  raised,  and  a  little  elevated. 
The  bar  signifies  that  all  the  numbers  under  it  are  to  be 
taken  together  ;  as  7+4-3=8  ;  or,  5x64^=50.  The 
parenthesis  ( )  is  sometimes  used  in  place  of  the  bar. 


166  SUMMARY  OF  ARITHMETIC. 


SUMMARY  OF  ARITHMETIC. 


The  following  abridgment  of  several  of  the  rules  of  arith- 
metic, often  referred  to  in  elementary  books  on  mechanical 
science,  are  here  inserted  for  the  convenience  of  reference. 
These  rules  and  examples  are  given  merely  to  refresh  the 
memory,  it  being  taken  for  granted  that  the  reader  has 
already  acquainted  himself  with  the  principles  of  common 
arithmetic.  They  will,  ho  we  er,  be  found  serviceable,  both 
as  a  convenience  of  reference,  and  to  give  some  insight  to  the 
subjects  on  which  they  treat. 

DECIMAL  FRACTIONS. 

A  decimal  fraction  derives  its  name  fron  the  Latin  decem, 
"ten,"  which  denotes  the  nature  of  its  numbers,  representing 
the  parts  of  an  integral  quantity,  divided  into  a  tenfold  pro- 
portion. It  has  for  its  denominator  a  UNIT,  or  whole  thing, 
as  a  gallon,  a  pound,  a  yard,  &c.,  and  is  supposed  to  be 
divided  into  ten  equal  parts,  called  tenths  ;  those  tenths  into 
ten  equal  parts,  called  hundredths,  and  so  on,  without  end. 

The  denominator  of  a  decimal  being  always  known  to  con- 
sist of  a  unit,  with  as  many  ciphers  annexed  as  the  numera- 
tor  has  places,  is  never  expressed,  being  understood  to  be  10, 
100,  1000,  &c.,  according  as  the  numerator  consists  of  1,  2,  3, 
or  more  figures.  Thus  :  -^  -f^  -f-fifa  &c.,  the  numerators 
only  are  written  with  a  dot  or  comma  before  them,  thus  -2 
'24  '125. 


SUMMARY  OF  ARITHMETIC.  1G7 

The  use  of  the  dot  (•)  is  to  separate  the  decimal  from  the 
whole  numbers. 

The  first  figure  on  the  right  of  the  decimal  point  is  in  the 
place  of  tenths,  the  second  in  the  place  of  hundredths,  the 
third  in  the  place  of  thousandths,  &c.,  always  decreasing 
from  the  left  towards  the  right  in  a  tenfold  ratio,  as  in  the 

following 

TABLE. 


Descending 

A  cipher  placed  on  the  left  hand  of  a  decimal  decreases  its 
value  in  a  tenfold  ratio  by  removing  it  farther  from  the 
decimal  point.  But  annexing  a  cipher  to  any  decimal  does 
not  alter  its  value  at  all.  Thus  0*4  is  ten  times  the  value  of 
0-04,  and  a  hundred  times  0'004.  But  0'7=0-70=0-700= 
0-7000,  &c.,  as  above  remarked. 

0-2        is  read  two-tenths. 

0-25       "     "    twenty-fire  hundredths. 

0-375     "     "    three  hundred  and  seventy -five  thousandths. 

0'1876  "  "  one  thousand  eight  hundred  and  seventy -six 
ten  thousandths,  and  so  on. 

Mixed  numbers  consist  of  a  whole  number  and  a  decimal ; 
as  4-25  and  3 -875. 


168 


SUMMARY  OF  ARITHMETIC. 


ADDITION  OP  DECIMALS. 

Rule. — Arrange  the  numbers  so  that  the  decimal  points 
shall  be  directly  over  each  other,  and  then  add  as  in  whole 
numbers,  and  place  the  decimal  point  directly  below  all  the 
other  points. 


read  5  Tenths, 
read  7  Hundredths. 
read  30  Thousandths, 
read  1248  Ten  Thousandths, 
read  8  and  6  Tenths, 
read  7  and  8  Millionths. 
read  84  and  25  Hundredths. 
read  5  and  6  Ten  Millionths. 
read  480. 

read  585  and  5748086  Ten 
Millionths. 


FRACTIONS. 

T5ff     is  the  same  as     '5 

7                 « 
ifo 

•07 

,80,.          tt 

looo 

•030 

fltofr     " 

•1248 

8iV      " 

8-6 

'  1000000 

7-000008 

84T2uS      " 

84-25 

"ITRTDOOOO 

5-0000006 

480      " 

"      480- 

585-5748086 

SUBTRACTION  OF  DECIMALS. 

Rule. — Place  the  numbers  directly  under  each  other, 
according  to  their  several  values,  as  in  addition ;  then  sub- 
tract as  in  whole  numbers,  and  point  off  the  decimals,  as  in 
the  last  rule 

Example.— Subtract  7*75  from  15-135. 

15-125 

7-75 

7 '375  remainder. 


SUMMARY  OF  ARITHMETIC,  169 

MULTIPLICATION  OF  DECIMALS. 

. — Place  the  factors  under  each  other,  and  multiply 
them  together  as  in  whole  nnmbers ;  then  point  off  as  many 
figures  from  the  right  hand  of  the  product  as  there  are 
decimal  places  in  both  factors,  observing,  if  there  be  not 
enough,  to  annex  as  many  ciphers  to  the  left  hand  of  the 
product  as  will  supply  the  deficiency. 

Example.—  Multiply  3 -625  by  2-75. 

3-625x2-75=9-96875.     Ans. 

DIVISION  OF  DECIMALS. 

Rule. — Prepare  the  decimal  as  directed  for  multiplication ; 
divide  as  in  whole  numbers ;  cut  off  as  many  figures  for  deci- 
mals in  the  quotient  as  the  number  of  decimals  in  the  dividend 
exceeds  the  number  in  the  divisor ;  and  if  the  places  in  the 
quotient  be  not  so  many  as  the  rule  requires,  supply  the 
deficiency  by  annexing  ciphers  to  the  left  hand  of  the 
quotient. 

Example  1,—  Divide  173-5425  by  3-75. 

3 -75)173  •5425(46-27 
1500 

2354 
2250 

1042 
750 

2925 
2625 

loo 


170  SUMMARY  OF  ARITHMETIC. 

Example  2.— Divide  63-50  by  4-25. 

4-25)63-50(14-94 
425 

2100 
1700 

4000 
3825 

1750 
1700 


RULE  OF   THREE,   OR  PROPORTION. 

The  Rule  of  Three  teaches  how  to  find  a  fourth  propor- 
tional term  to  three  given  numbers. 

The  rule  of  three  is  either  direct  or  inverse. 

When  more  requires  more,  or  less  requires  less,  it  is  direct. 
Thus,  if  5  barrels  of  beef  cost  §30,  what  will  12  barrels  cost  ? 
Or,  if  30  cubic  inches  of  cast  iron  weigh  8  Ibs.,  what  will  378 
cubic  inches  weigh  ? 

The  proportion  in  both  of  the  above  cases  is  direct,  and  the 
statement  must  be 

As  5  :  30  :  :  12  :  4th  term=72     Ans. 
30  :    8  :  :  378  :       "        =  100£  Ibs.     Ans. 

When  more  requires  less,  or  less  requires  more,  the  rule  is 
inverse.  Thus,  if  3  men  do  a  certain  piece  of  work  in  5  days, 
in  how  many  days  will  4  men  do  the  like  quantity  ?  Or,  if 
12  men  build  a  certain  quantity  of  wall  in  28  days,  ID  uow 
many  days  will  8  men  perform  the  same  work  ? 


SUMMARY  OF  ARITHMETIC.  171 

Here  the  proportion  is  inverse,  and  the  statement  must  be 

4:    5::    3  :  4th  term=3f.     Ans. 
S*  8  :  28  :  :  12  :        "        =42.     Ans. 

The  product  of  the  second  and  third  terms,  divided  by  the 
first,  always  gives  the  fourth  term. 

Three  numbers  are  necessary  for  a  statement ;  and  two  of 
these  must  contain  the  supposition,  and  the  third  the  demand. 

Rule. — Of  the  three  given  numbers,  place  that  for  the  third 
term  which  is  of  the  same  kind  with  the  answer  sought. 

Then  consider,  from  the  nature  of  the  question,  whether 
the  answer  will  be  greater  or  less  than  this  term.  If  the 
answer  is  to  be  greater,  place  the  greater  of  the  two  numbers 
for  the  second  term,  and  the  less  number  for  the  first  term ; 
but  if  it  is  to  be  less,  place  the  less  of  the  two  remaining  num- 
bers for  the  second  term,  and  the  greater  for  the  first ;  and 
in  either  case  multiply  the  second  and  third  terms  together, 
and  divide  the  product  by  the  first  for  the  answer,  which  will 
always  be  of  the  same  denomination  as  the  third  term. 

NOTE.— If  the  first  and  second  terms  contain  different  denomina- 
tions, they  must  both  be  reduced  to  the  same  denomination;  and 
compound  numbers  to  integers  of  the  lowest  denomination  contained 
in  it. 

Example. — If  40  tons  of  iron  cost  $450,  what  will  130  tons 
cost? 

TONS.  DOLLS.    TONS. 

40  :  450  :  :  130 
130 


13500 
450 

4(0)585010 

1462 -5  dollars.     Ans. 


172  SUMMARY  OF  ARITHMETIC. 


ARITHMETICAL  PROGRESSION. 


Arithmetical  Progression  is  a  series  of  numbers  which 
succeed  each  other  regularly,  increasing  or  diminishing  by  a 
constant  number  or  common  difference  : 

As    1,  3,  5,  7,  9,  &c.  j  increasing  series. 
15,  12,  9,  6,  3,  &c.  }  decreasing  series. 

The  numbers  which  form  the  series  are  called  terms.  The 
first  and  the  last  term  are  called  the  extremes,  and  the  others 
are  called  the  means. 

In  arithmetical  progression,  there  are  five  things  to  be  con- 
sidered, viz. : 

1,  The  first  term. 

2,  The  last  term. 

8,  The  common  difference. 

4,  The  number  of  terms. 

5.  The  sum  of  all  the  terms. 

These  quantities  are  so  related  to  each  other,  that  when 
any  three  of  them  are  given,  the  remaining  two  can  be  found 

Given  the  first  term,  the  common  difference,  and  the  num- 
ber of  terms,  to  find  the  last  term. 

Rule. — Multiply  the  number  of  terms,  less  one,  by  the 
common  difference,  and  to  the  product  add  the  first  term. 


StTMMAttY  OP  AttlTBMETlC. 


Example.  —  What  is  the  20th  term  of  the  arithmetical  pro- 
gression, whose  first  term  is  1,  the  common  difference  £  ? 
20—1  =  19  and  19x=9;  and  91  =  10.     Ans. 


Given  the  number  of  terms  and  the  extremes,  to  find  the 
common  difference. 

Rule.—  Divide  the  difference  of  the  extremes  by  one  less 
than  the  number  of  terms. 

Example.  —  The  extremes  are  3  and  29,  and  the  number  of 
terms  14,  required  the  common  difference. 

29—  3=26;  and  26  -hi  3=  2.     Ans. 

Given  the  common  difference  and  the  extremes,  to  find  the 
number  of  terms. 

Rule.  —  Divide  the  difference  of  the  extremes  by  the  com- 
mon difference,  and  to  the  quotient  add  one. 

Example.  —  The  first  term  of  an  arithmetical  progression  is 
11,  the  last  term  88,  and  the  common  difference  7.  What  is 
the  number  of  terms  ? 

88—11  =  77;  and77-h7=ll;  11+1=12.     Ans. 

Given  the  extremes  and  the  number  of  terms,  to  find  the 
sum  of  all  the  terms.  . 

Rule.  —  Multiply  half  the  sum  of  the  extremes  by  the  num- 
ber of  terms. 

Example.  —  How  many  times  does  the  hammer  of  a  clock 
strike  in  12  hours  ? 

l-f-12=13  the  sum  of  the  extremes. 
Then    12  X  (13  -=-2)  =78.     Ans. 


J74  RULE  FOR  SETTING 


TO  SET  THE  VALVES  OF  A  CORLISS 
ENGINE.* 


And  make  proper  adjustment  of  valve  gear  and  regulator, 
please  read  carefully  and  follow  the  instructions  here  given  : 

THE  STEAM  AND  EXHAUST  VALVES. — Take  off  the  back 
valve  chest  cover  or  bonnets  and  upon  the  bore  of  the  seats 
you  will  find  a  mark  which  is  in  line  with,  or  coincides  with 
the  closing  edge  of  the  port  for  that  particular  valve  seat. 
Look  upon  the  end  of  the  valve  and  find  a  mark  running 
towards  the  centre  of  the  valve ;  this  line  coincides  with  the 
closing  edge  of  valve.  Note  that  in  case  of  the  exhaust 
valve,  the  valve  controls  the  part  leading  into  the  exhaust 
passage  and  not  the  opening  from  the  cy Under  downward. 
The  upper  edge  of  the  exhaust  port  is  the  closing  edge  and 
the  outer  edges  of  the  steam  ports  are  the  closing  edges. 

THE  WRIST  PLATE — should  now  be  looked  over  and  you 
will  find  a  mark  upon  the  hub  of  the  same,  and  correspond- 
ing marks  upon  the  hub  of  the  wrist  plate  bracket.  Also 
marks  which  show  the  full  extent  of  motion  of  the  wrist 
plate  when  it  is  moved  back  and  forth  by  the  eccentric.  The 
wrist  plate  should  be  located  exactly  central  between  the 
four  valves  and  is  so  placed  in  the  shop  in  building  the 


*  These  directions  are  given  by  E.  P.  Hampson  to  accompany  the 
Eclipse  Corliss  Engine,  and  are  sufficiently  general  to  answer  for  any 
Corliss  Engine. 


OORLTSS  BUYING   VALVES.  175 

machine,  and  all  adjustments  are  made  and  valves  properly 
set,  but  in  taking  apart  for  adjustment  it  may  be  possible 
that  the  adjustments  may  be  distributed  and  need  careful 
going  over  before  attempting  to  start  the  engine  for  the  first 
time. 

To  TEST  THE  MARKS  ON  WRIST  PLATE  HUB — connect  the 
eccentric  rods  and  engage  or  drop  the  carrier  rod  back  upon 
the  wrist  plate  stud  ;  then  turn  the  eccentric  upon  the  shaft, 
the  full  extent  of  its  throw  or  vibration  each  way,  and 
observe  if  the  marks  upon  the  hub  of  wrist  plate  at  full 
throw  agree  with  the  marks  upon  the  bracket ;  if  not,  dis- 
connect the  strap  from  eccentric  rod,  and  adjust  the  screw 
on  stub  end  by  lengthening  or  shortening,  as  required,  until 
the  marks  do  agree  on  both  extremes  of  movement.  Now 
you  are  ready 

To  SET  THE  VALVES.— Place  the  wrist  plate  in  a  vertical 
position  (at  the  central  mark)  ;  turn  the  valves  around  in 
their  seats  until  the  steam  valves  show  by  the  closing  edge 
marks  upon  their  ends  by  comparison  with  the  port  line 
marks  in  the  seats,  that  the  steam-valve  edges  lap  over  or 
cover  the  ports  £  of  an  inch  for  18  inch  bore  of  engine 
cylinder,  f  for  24-inch  cylinder,  and  T7^  for  30-inch  cylinder. 
The  exhaust  valves  should  show  from  T^  to  £  lap,  ac- 
cording to  size  of  cylinder. 

IN  CONNECTING  THE  WRIST  PLATE— see  first  that  the  cut-off 
latch  is  hooked  on  the  stud  or  is  engaged.  Leave  the  plate 
and  valves  in  this  position  and  adjust  the  length  of  the  wrist 
plate  rods  to  suit  the  distances  between  the  studs,  or,  in  other 
words,  connect  the  wrist  plate  and  steam  and  exhaust  valve 


170  RULE  FOR  SETTING 

arms  so  the  wrist  plate  stands  at  the  central  mark  or  vertical, 
and  the  steam  and  exhaust  valve  have  the  proper  lap  and 
opening  as  instructed,  the  proper  amount  of  steam  lap  and 
exhaust  opening  being  determined  by  the  size  of  the  engine. 

To  MAKE  FINAL  ADJUSTMENTS.— Now  you  can  drop  the 
wrist  plate  carrier  rod  hook  on  the  stud,  place  the  engine 
upon  the  centre,  knowing  "which  way  the  engine  shaft  is  to 
run,  turn  the  eccentric  upon  the  shaft,  it  being  loose,  in  the 
same  direction  in  which  the  shaft  is  to  run,  a  little  more 
than  at  right  angles  ahead  of  the  crank  or  until  the  steam 
valve  on  the  same  end  as  the  piston  is  just  beginning  to  open, 
say  -^  of  an  inch — in  this  position  secure  the  eccentric  on  the 
shaft  by  means  of  the  set  screws  in  the  hub.  (See  in  all 
cases  that  the  steam  valves  are  hooked  up  or  engaged  by  the 
cut-off  mechanism.)  Then  turn  the  engine  on  the  opposite 
centre  and  see  if  the  steam  valve  on  that  end  has  the  same 
amount  of  opening  ;  if  not,  you  can  make  the  adjustment  by 
lengthening  or  shortening  the  wrist  plate  rod  attached  to 
this  valve. 

To  ADJUST  THE  CUT-OFF,  see  that  the  governor  and 
connections  are  put  together  properly,  and  block  the  gover- 
nor about  half  way  in  the  slot ;  then  fasten  the  reach  or  cam 
rod  lever  so  it  stands  about  at  right  angles  to  a  line  drawn 
midway  between  the  reach  rods ;  then  lengthen  or  shorten 
the  reach  rods  until  the  cam  or  trip  levers  stand  vertical  or 
plumb.  The  governor  and  connections  now  occupy  the 
proper  relative  positions,  and  it  remains  to  make  the 

EXA.CT  ADJUSTMENT  and  to  equalize  the  cut-off,  so  the 
same  amount  of  steam  is  admitted  at  each  end  of  the  stroke. 


CORLISS  ENGINE  VALVES.  377 

Also,  lower  the  governor  and  observe  when  the  governor  is 
down  that  the  cut-off  mechanism  does  not  unhook  but  allows 
steain  to  be  taken  full  stroke,*  after  which  place  the  engine 
at,  say  ^  of  the  stroke,  which  can  be  done  by  measuring  upon 
the  slide  ways  from  each  end  and  turning  the  engine  (with 
all  parts  connected  up)  until  crosshead  is  fair  with  the  mark, 
then  slowly  raise  the  governor  until  the  cut-off  on  the  end 
taking  steam  trips  or  uuhooks,  and  to  insure  this  point 
being  accurately  determined,  it  is  well  to  stand  by  with  the 
hand  pressing  down  upon  the  dash-pot  rod ;  now  block  the 
governor  in  this  position  and  try  the  cut-off  on  the  other 
stroke  same  distance  from  the  end.  After  a  few  trials  back 
and  forth  and  adjusting  the  length  of  the  cam  rods,  the 
cut-off  can  be  made  to  drop  at  precisely  the  same  point  of 
stroke.  Take  care  to  secure  everything  permanently  when 
done. 

THE  DASH-POT  ROD  should  be  adjusted  in  length  so  the 
steam  valve  arm  resting  thereon,  when  the  dash-pot  plunger 
is  home,  or  at  the  bottom  of  the  pot,  is  in  such  a  position 
that  the  latch  is  sure  to  hook  over  the  latch  stud,  and  the 
stud  lays  midway  between  the  latch  die  and  the  closing 
shoulder.  This  will  insure,  on  the  other  hand,  the  positive 
engagement  of  the  latch,  and  on  the  other  hand  prevent  the 
eho  alder  from  jamming  down  upon  the  latch  stud  in  steam 
arm.  If  the  dash-pot  rod  is  too  short  the  latch  will  not  hook 
on.  Look  out  for  this. 


*  Here  we  would  say  that  it  does  not  appear  to  be  generally  known 
that  the  Corliss  valve  motion,  when  properly  made,  is  provided  with 
a  positive  closing  device  which,  in  case  the  valve  does  not  trip,  posi- 
tirely  closes  the  valve  before  piston  reaches  the  end  of  the  stroke. 


178  CORLISS  ENGINE 


THE  DASH-POT  is  provided  with  a  leather  packing  in  the 
vacuum  plunger  underneath  the  dash-pot  proper.  This  should 
be  kept  in  good  condition.  To  spread  the  packing  introduce 
some  liners  of  paper  inside  the  flange  or  cup  leather.  When 
leather  is  adjusted  just  right  the  pot  works  promptly  and 
softly.  The  air  valve  in  the  air  opening  is  to  regulate  the 
amount  of  air  cushion  by  turning  the  screw  in  the  escape 
hole. 

THE  REGULATOR  GAG-POT  is  used  on  Corliss  engines  to 
prevent  over-sensitiveness  of  the  governor,  and  to  its  re- 
sponse to  trivial  changes.  Use  only  coal  or  kerosene  oil  in 
this  pot,  and  remove  one  or  more  of  the  screws  in  the  piston 
to  give  freedom  of  motion.  See  that  all  parts  of  the  gover- 
nor move  freely. 

USING  A  STEAM  ENGINE  INDICATOR  to  test  the  correctness 
of  valve  setting  is  the  most  approved  method  known,  and 
should  be  applied  in  cases  where  an  indicator  can  be  obtained. 
Recollect  that  to  adjust  the  point  of  cut-off  to  take  same 
amount  of  steam  to  each  end,  adjust  the  cam  or  reach  rods. 
To  give  more  or  less  lead  adjust  the  wrist  plate  rods. 
Lengthening  them  increases  the  lap,  and  shortening  them 
gives  more  lead.  The  same  with  the  exhaust  valves,  the 
cushion  or  release  being  affected  thereby.  If  the  eccentric 
is  properly  set  it  is  not  necessary  to  disturb  it  in  ordinary 
cases.  In  closing  these  directions,  let  us  impress  upon  you 
the  necessity  of  marking  everything,  so  at  a  glance  you  can 
tell  if  it  has  been  disturbed. 


RULES  USEFUL  TO  THE  ENGINEER. 


EMERGENCY  RULE  FOR  SETTING  SLIDE  VALVES. 

If  the  eccentric  slips  around  the  shaft,  or  any  other  acci- 
dent throws  the  valve-gear  out  Of  position,  then, 

1.  Have  some  one  roll  the  engine  forward  in  the  direction 
it  runs  until  the  crank  is  on  the  dead  centre. 

2.  Open  the  cylinder  cocks  at  each  end. 

3.  Admit  a  small  amount  of  steam  into  the  steam  -chest  by 
opening  the  throttle  slightly. 

4.  Eoll  the  eccentric  forward,  in  the  direction  the  engine 
runs,  until  steam  escapes  from  the  cylinder  cock  at  the  end 
where  the  valve  should  begin  to  open. 

5.  Screw  your  eccentric  fast  to  the  shaft. 

6.  Roll  your  crank  around  to  the  next  centre,  and  ascertain 
if  steam  escapes  at  the  same  point,  at  the  opposite  end  of  the 
cylinder.     If  so,  the  valve  is  in  position  for  service,  until  an 
opportunity  occurs  to  open  the  steam-chest  and  examine  the 
valve-gear. 

EMERGENCY  RULE  FOR  SETTING  DUPLEX  PUMP  VALVES. 

Take  off  the  valve  chest  cover,  push  the  piston  to  water 
end,  mark  the  piston  rod  by  tying  a  string  at  the  gland,  then 
push  same  piston  to  stem  end  and  tie  another  string  around 
it.  Find  the  center  between  the  two  marks  and  move  the 
piston  until  the  centre  mark  reaches  the  gland  where  the 
first  mark  was  made.  After  this  is  done  see  how  the  valve  is 
for  lead  ;  if  equal  at  both  ends  your  valve  is  set,  if  not,  adjust 
your  jam  nuts  to  suit  Work  the  same  way  with  the  other 
piston. 


180  A  PRELIMIKARr  EXAMINATION. 


A  PRELIMINARY  EXAMINATION  CONDUCTED 
BY  ONE'S  SELF. 


1.  Can  I  build  and  maintain  a  fire  with  an  intensity  of 
heat  sufficient  to  hold  a  working  pressure  of  steam  ?  2.  Can 
I  fire  with  soft  coal  and  prevent  smoke  issuing  from  my 
chimney  in  too  large  volumes  ?  3.  Can  I  pack  the  valve 
stems,  chest  covers  and  piston  rods  of  the  engine  and  feed 
pump  ?  4.  Can  I  line  up  shafting  ?  5.  Can  I  lace  up  a  belt 
in  a  suitable  manner  and  run  it  on  the  pulley  safely  ?  6.  Do 
I  understand,  and  can  I  replace  the  working  points  of  the 
feed  pump  when  they  become  worn  ?  7.  Can  I  determine, 
by  its  action,  whether  pump  is  delivering  water  to  the  boiler 
or  not  ?  8.  If  not,  can  I  tell  where  the  difficulty  exists  ? 

A  chief  engineer's  position  is  no  sinecure.  It  requires 
constant  study,  thought  and  action.  It  takes  men  of  hard 
brains  to  fill  soft  situations,  it  also  requires  years  of  applica- 
tion for  brains  to  harden,  hence  one  too  young  or  inexperi- 
enced should  hesitate  in  accepting  a  position  \vhich  they 
know  they  cannot  possibly  fill  with  mutual  profit  to  them- 
selves or  the  owners. 

Elementary   and   Preliminary   Questions   by   the 
Examining  Engineer. 

Thfise  questions  are  given  as  those  frequently  asked  of  the 
applicant  upon  his  first  appearance  for  examination. 

1.  Where  and  how  long  did  you  serve  in  the  works  at  the 
making  or  at  the  repairing  of  engines  and  in  what  capacities? 


A  PRELIMINARY  EXAMINATION. 


2.  How  long  have  you  served  as  fireman  ?  How  long  have 
you  been  employed  as  an  engineer,  and  where?  8.  Give 
some  further  idea  of  the  extent  of  your  experience  as  an 
engineer.  4.  What  kind  of  engines  are  you  familiar  with  ? 
Marine  or  land,  condensing  or  non-condensing,  horizontal, 
compounds,  etc.?  5.  What  defects  in  engines  have  come 
under  your  notice  ?  6.  What  caused  these  defects  and  how 
were  they  remedied  ?  7.  With  what  description  of  boilers 
have  you  served  ?  S.  Describe  a  horizontal  tubular  boiler. 
9.  Describe  a  vertical  boiler.  10.  What  boiler  defects  have 
come  under  your  notice  and  how  have  they  been  remedied  ? 
1  1.  Have  you  ever  witnessed  a  steam  boiler  explosion,  and  if 
so,  give  the  cause  ?  12.  Give  the  names  of  the  firms  for 
whom  you  have  served  or  vessels  upon  which  you  have  been 
engaged  ?  13.  What  parts  of  the  engine  are  usually  of  cast 
iron  ?  14.  For  what  parts  of  an  engine  is  steel  sometimes 
used?  15.  What  are  hand  holes  put  in  boilers  for  ?  16.  How 
often  do  you  open  them  ?  17.  What  is  the  shape  of  a  man 
hole  cover,  and  about  what  is  its  size  ?  18.  What  is  priming 
in  a  boiler  and  what  means  are  taken  to  prevent  it  ? 

NOTE.  —  A  boilermaker  says  that  never  before  have  boiler  materials 
been  of  better  quality  than  they  are  to-day.  A  contrary  belief  is  often 
expressed  ;  but  modern  mastery  of  steel  making  has  lessened  the  mar- 
gin between  good  steel  and  inferior  steel.  The  danger  with  boiler 
making  is  not  poor  steel,  but  poor  workmanship.  Badly  spaced  tubes, 
rivets  and  braces,  plates  too  thin  for  the  work,  deficient  safety  attach- 
ments, and  ill-proportioned  settings  are  points  where  the  ignorant  or 
dishonest  make  a  cheap  and  dangerous  boiler. 


182  IT.  8.  RULES  FOR  SA&ETT  VAX.VTQS, 


U.  S.  GOVERNMENT  RULES  FOR  THE  SAFETY 
VALVE. 


The  following  rules  issued  by  the  United  States  Board  of 
of  Supervising  Inspectors,  on  account  of  changes  in  the  rules 
for  granting  licenses  to  engineers  of  steam  vessels,  are 
entirely  accurate  for  use  in  figuring  the  different  problems 
relating  to  the  safety  valve. 

To  find  the  weight  required  to  load  a  given  safety-valve  to 
blow  at  any  specified  pressure. 

1.  Measure  the  diameter  of  the  valve,  if  is  it  not  known, 
and  from  this  compute  its  area  exposed  to  pressure. 

2.  Weigh  the  valve  and  its  spindle.*    If  it  is  not  possible 
to  do  this,  compute  their  weight  from  their  dimensions  as 
accurately  as  possible. 

3.  Weigh  the  lever,  or  compute  its  weight  from  its  dimen- 
sions. 

4.  Ascertain  the  position  of  the  centre  of  gravity  of  the 
lever  by  balancing  it  over  a  knife-edge,  or  some  sharp-cor- 
nered article,  and  measuring  the  distance  from  the  balancing 
point  to  the  fulcrum. 


*  To  find  the  weight  of  the  valve,  spindle,  lever,  etc.,  proceed  as  fol- 
lows :  Take  out  the  valve  and  spindle  and  weigh  them  and  make  a 
note  of  it,  then  put  them  back  in  place,  connect  the  lever  and  drop  it 
in  place  resting  on  the  valve  spindle,  tie  a  string  to  the  lever  directly 
over  the  spindle,  hook  on  the  scales  to  the  string  and  weigh  the  lever, 
to  the  weight  of  the  lever  add  the  weight  of  valve  and  spindle,  or  the 
weight  may  be  found  approximately  by  computation. 


IT.  &  RULES  FOR  SAFETY  VALVES.  183 

5.  Measure  the  distance  from  the  center  of  the  valve  to 
the  fulcrum. 

6.  Measure  the  distance  from  the  fulcrum  to  the  center  of 

the  weight. 

Then  compute  the  required  weight  as  follows  : 

1.  Multiply  the  pressure  in  pounds  per  square  inch  at  which 
the  valve  is  to  be  set  by  the  area  of  the  valve  in  square 
inches;  set  the  product  aside  and  designate  it  "quantity 
No.  1." 

2.  Multiply  the  weight  of  the  lever  in  pounds  by  the  dis- 
tance in  inches  of  its  center  of  gravity  from  the  fulcrum  ; 
divide  the  product  by  the  distance  in  inches  from  the  center 
of  the  valve  to  the  fulcrum,  and  add  to  the  quotient  the 
weight  of  the  valve  and  spindle  in  pounds ;  set  the  sum  aside 
and  designate  it  "  quantity  No.  2." 

3.  Divide  the  distance  in  inches  from  the  center  of  the 
valve  to  the  fulcrum  by  the  distance,  also  expressed  in  inches, 
from  the  center  of  the  weight  to  the  fulcrum  ;  designate  the 
quotient  "quantity  No.  3." 

4.  Subtract  quantity  No.  2  from  No.  1,  and  multiply  the 
difference  by  No.  3.    The  product  will  be  the  required  weight 
in  pounds. 

To  find  the  length  of  the  lever,  or  distance  from  the  fulcrum 
at  which  a  given  weight  must  be  set  to  cause  the  valve  to  blow 
at  any  specified  pressure. 

The  area  of  the  valve  in  square  inches,  the  weight  of  the 
valve,  spindle  and  lever  in  pounds,  the  position  of  the  center 
of  gravity  of  the  lever,  and  the  distance  from  the  center  of 


184 u.  $.  RULES  FOR  SAFETY  VALVES. 

the  valve  of  the  fulcrum,  must  be  known,  as  in  the  first 
example. 

Then  compute  the  required  length  as  follows 

1.  Multiply  the  area  of  the  valve  in  square  inches  by  the 
pressure  in  pounds  per  square  inch  at  which  it  is  required  to 
blow  ;  set  the  product  aside,  and  designate  it  "  No.  1." 

2.  Multiply  the  weight  of  the  lever  in  pounds  by  the  dis- 
tance in  inches  of  its  center  of  gravity  from  the  fulcrum  ; 
divide  the  product  by  the  distance  in  inches  from  the  center 
of  the  valve  to  the  fulcrum  ;  add  to  the  quotient  the  weight 
of  the  valve  and  spindle  ;  set  the  sum  aside,  and  designate  it 
"No.  2." 

3.  Divide  the  distance  in  inches  from  the  center  of  valve 
to  fulcrum  by  the  weight  of  the  ball  in  pounds,  and  call  the 
quotient  "No.  3." 

4.  Subtract  "No.  2"  from  "  No.  1,"  and  multiply  the 
difference  by  "  No.  3  " ;  the  product  will  express  the  distance 
in  inches  that  the  ball  must  be  placed  from  the  fulcrum  to 
produce  the  required  pressure. 

To  find  at  what  pressure  the  safety  valve  will  commence  to 
Wow  when  the  weight  and  its  position  on  the  lever  are  known. 

The  weight  of  valve,  lever,  position  of  centre  of  gravity  of 
lever,  etc.,  must  be  known  as  in  both  the  preceding  examples. 

Then  compute  the  pressure  at  which  the  valve  will  blow, 
as  follows  : 

Multiply  the  weight  of  the  lever  by  the  distance  of  iti 
center  of  gra>  ity  from  the  fulcrum ;  add  to  this  product  that 
obtained  by  multiplying  the  weight  of  the  ball  by  its  distance 


V.  8.  RULES  FOR  SAFETY  VALVES.  186 

from  the  fulcrum  ;  divide  the  sum  of  these  two  products  by 
the  distance  from  the  center  of  the  valve  to  the  fulcrum,  and 
add  to  the  quotient  so  obtained  the  weight  of  the  valve  and 
spindle.  Divide  the  sum  by  the  area  of  the  valve  ;  the 
quotient  will  be  the  required  blowing-off  pressure  in  pounds 
per  square  inch. 

EXAMPLE. 

Suppose  we  have  a  safety  valve,  with  a  weight  of  60  Ibs, 
suspended  24  inches  from  the  fulcrum  ;  say  the  lever  weighs 
6  Ibs.,  gravity  center  (balancing  point)  15  inches  from  the 
fulcrum,  weight  of  valve  and  spindle  2  Ibs. ,  and  its  center  4 
inches  from  the  fulcrum,  and  the  diameter  of  the  valve  2 
inches,  at  what  pressure  will  the  valve  open  ?  Now,  then: 

Diameter  of  valve  is  2  inches  ;  its  square  is  2x2=4  ;  its 
area  is  0.7854x4=3.1416;  the  weight  of  the  ball  is  50  Ibs.,  its 
distance  from  fulcrum  is  24  inches,  and  50x24=1,200  ;  the 
weight  of  lever  is  6  Ibs.,  the  center  of  gravity  is  15  inches 
from  the  fulcrum,  and  15x6=90  ;  the  weight  of  the  valve  is 
2  Ibs.,  and  its  distance  is  4  inches  from  fulcrum,  and  4x2=8; 
the  area  of  the  valve  is  3. 1416,  and  its  center  is  4  inches  from 
fulcrum,  then  4x3.1416=12.5664,  and  1200+90+8=1298,  and 
1298  divided  by  12.5664=103.3  Ibs.,  or  the  pressure  at  which 
the  valve  will  open*. 


*  The  "  moment "  or  leverage  of  the  steam  is  the  total  pressure 
acting  upwards,  multiplied  by  the  distance  in  inches  from  the  pivot 
to  the  valve-stem.  The  moment  or  leverage  of  the  ball  acting  down- 
ward s  is  the  total  weight  of  the  ball  multiplied  by  the  distance  in 
inches  from  the  pivot  to  the  center  support  of  the  ball.  When,  there- 
fore, the  moment  of  the  steam,  which  acts  upwards,  exceeds  both  the 
dead  weight  of  the  lever  and  valve,  and  also  the  moment  of  the  ball 
holding  the  valve  down,  then  the  valve  rises  and  steam  escapes. 


186  tT.  S.  GOVERNMENT  RULES. 


U,  S.  GOVERNMENT  RULES  FOR  EXAMINA- 
TIONS OF  APPLICANTS  FOR  ENGINEERS' 
LICENSES. 


It  will  be  observed  that  in  land  service  the  engineer  is  ex. 
amined  with  reference  to  his  capacity  to  manage  a  particular 
steam  plant,  especially  the  steam  generating  apparatus.  He 
is  licensed  to  have  charge  of  a  particular  "plant"  and  for  a 
single  year ;  but  in  the  marine  service,  where  the  examina- 
tions are  conducted  by  sworn  officers  of  the  U.  S.  Navy,  the 
license  is  granted  without  reference  to  a  particular  craft, 
nor  is  it  limited  to  time,  except  the  candidate  is  subject  to 
re-examination;  the  marine  licenses,  however,  vary  as  to 
ocean  and  inland  steamers,  tug  boats,  etc. 


Regulations  Relating  to  Marine  Engineers. 

1.  Before  an  original  license  is  issued  to  any  person  to  act 
as  engineer,  he  must  personally  appear  before  some  local 
board  or  a  supervising  inspector  for  examination ;  but  upon 
the  renewal  of  such  license,  when  the  distance  from  any  local 
board  or  supervising  inspector  is  such  as  to  put  the  person 
holding  the  same  to  great  inconvenience  and  expense  to 
appear  in  person,  he  may,  upon  taking  the  oath  of  office  be- 


ENGINEERS1  EXAMINATIONS.  187 

fore  any  person  authorized  to  administer  oaths,  and  forward- 
ing the  same,  together  with  the  license  to  be  renewed,  to  the 
local  board  or  supervising  inspector  of  the  district  in  which 
he  resides  or  is  employed,  have  the  same  renewed  by  the 
said  inspectors,  if  no  valid  reason  to  the  contrary  be  known  to 
them;  and  they  shall  attach  such  oath  to  the  stub  end  of  the 
license,  which  is  to  be  retained  on  file  in  their  office.  And 
inspectors  are  directed,  when  licenses  are  completed,  to  draw 
a  broad  pen  and  red  ink  mark  through  all  unused  spaces  in 
the  body  thereof,  so  as  to  prevent,  so  far  as  possible,  illegal 
interpolation  after  issue. 

2.  The  classification  of  engineers  on  the  lakes  and  sea- 
board shall  be  as  f  ollows : 

CHIEF. 

Chief  engineer  of  ocean  steamers. 

Chief  engineer  of  condensing  lake,  bay  and  sound  steamers. 

Chief  engineer  of  non-condensing  lake,  bay  and  sound 
steamers. 

Chief  engineer  of  condensing  river  steamers. 

Chief  engineer  of  non -condensing  river  steamers. 

Chief  engineer  of  condensing  freight,  towing,  and  fishing 
steamers. 

Chief  engineer  of  non-condensing  freight,  towing,  and 
fishing  steamers. 

Chief  engineer  of  condensing  steamers  under  one  hundred 
tons. 

Chief  engineer  of  non-condensing  steamers  under  one  hun- 
dred tons. 

Chief  engineer  of  canal  steamers. 


188  U.  S.  GOVERNMENT  RULES. 

FIRST  ASSISTANT. 

First  assistant  engineer  of  ocean  steamers. 

First  assistant  engineer  of  condensing  lake,  bay,  and  sound 
steamers. 

First  assistant  engineer  of  non-condensing  lake,  bay,  and 
sound  steamers. 

First  assistant  engineer  of  condensing  river  steamers. 

First  assistant  engineer  of  non-condensing  river  steamers. 

First  assistant  engineer  of  condensing  freight,  towing,  and 
fishing  steamers. 

First  assistant  engineer  of  non-condensing  freight,  towing, 
and  fishing  steamers. 

First  assistant  engineer  of  condensing  steamers  under  one 
hundred  tons. 

First  assistant  engineer  of  non-condensing  steamers  under 
one  hundred  tons. 

First  assistant  engineer  of  canal  steamers. 

SECOND  ASSISTANT. 

Second  assistant  engineer  of  ocean  steamers. 

Second  assistant  engineer  of  condensing  lake,  bay,  and 
sound  steamers. 

Second  assistant  engineer  of  non-condensing  lake,  bay,  and 
sound  steamers. 

Second  assistant  engineer  of  condensing  river  steamers. 

Second  assistant  engineer  of  non-condensing  river  steam- 
ers. 

Second  assistant  engineer  of  condensing  freight,  towing, 
and  fishing  steamers. 

Second  assistant  engineer  of  non-condensing  freight,  tow- 
ing and  fishing  steamers. 


ENGINEERS'  EXAMINATIONS.  JS9 

Second  assistant  engineer  of  condensing  steamers  under 
one  hundred  tons. 

Second  assistant  engineer  of  non-condensing  steamers 
under  one  hundred  tons. 

THIRD  ASSISTANT. 

Third  assistant  engineer  of  ocean  steamers. 

Third  assistant  engineer  of  condensing  lake,  bay,  and 
sound  steamers. 

Third  assistant  engineer  of  non- condensing  lake,  bay,  and 
sound  steamers. 

Third  assistant  engineer  of  condensing  river  steamers. 

Third  assistant  engineer  of  non-condensing  river  steamers. 

Third  a  ssistant  engineer  of  condensing  freight,  towing,  and 
fishing  steamers. 

Third  assistant  engineer  of  non-condensing  freight,  towing 
and  fishing  steamers. 

First,  second,  and  third  assistant  engineers  may  act  as 
such  on  any  steamer  of  the  grade  of  which  they  hold  license, 
or  as  such  assistant  engineer  on  any  steamer  of  a  lower  grade 
than  those  to  which  they  hold  a  license. 

Inspectors  may  designate  upon  the  certificate  of  any  chief 
or  assistant  engineer  the  tonnage  of  the  vessel  on  which  he 
may  act. 

3.  Assistant  engineers  may  act  as  chief  engineers  on  high- 
pressure  steamers  of  one  hundred  tons  burden  and  under,  of 
the  class  and  tonnage,  or  particular  steamer  for  which  the 
inspectors,  after  a  thorough  examination,  may  find  them 
qualified.  In  all  cases  where  an  assistant  engineer  is  per- 
mitted to  act  as  first  (chief)  engineer,  the  inspector  shall  state 


190  u-  s-  GOVERNMENT  RULES. 

on  the  face  of  his  certificate  of  license  the  class  and  tonnage 
of  steamers,  or  the  particular  steamer  on  which  he  may  so 
act. 

4.  It  shall  be  the  duty  of  an  engineer  when  he  assumes 
charge  of  the  boilers  and  machinery  of  a  steamer,  to  forth- 
with thoroughly  examine  the  same,  and  if  he  finds  any  part 
thereof  in  bad  condition,  caused  by  neglect  or  inattention  on 
the  part  of  his  predecessor,  he  shall  immediately  report  the 
facts  to  the  local  inspectors  of  the  district,  who  shall  there- 
upon investigate  the  matter,  and  if  the  former  engineer  has 
been  culpably  derelict  of  duty,  they  shall  suspend  or  revoke 
his  license. 

5.  No  person  shall  receive  an  original  license  as  engineer, 
or  assistant  engineer,   except  for  special  license  on  small 
pleasure  steamers  of  ten  tons  and  under,  and  ferry-boats 
navigated  outside  of  ports  of  entry  and  delivery,  who  has 
not  served  at  least  three  years  in  the  engineer's  department 
of  a  steam  vessel. 

Section  5.  (Second  paragraph  amended.)  Provided,  That 
any  person  who  has  served  as  a  regular  machinist  in  a  marine 
engine  works  for  a  period  of  not  less  than  three  years  (not 
including  any  time  he  may  have  served  as  an  apprentice, 
may  be  licensed  as  an  engineer  of  steam  vessels  of  one  hun- 
dred tons  and  under,  and  for  inferior  grade  of  license  above 
one  hundred  tons);  and  any  person  who  has  served  for  a 
period  of  not  less  than  three  years  as  a  locomotive  engineer, 
stationary  engineer,  regular  machinist  in  a  locomotive  or 
stationary  engine  works  (apprentice  machinist  in  an  engine 
works),  and  any  person  who  has  graduated  as  a  mechanical 


ENGINEERS'  EXAMINATIONS.  191 

engineer  from  a  duly  recognized  school  of  technology,  may 
be  licensed  to  serve  as  engineer  on  steam  vessels  after  having 
had  not  less  than  one  year's  experience  in  the  engine  depart- 
ment of  a  steam  vessel,  which  experience  must  have  been 
obtained  withimtwo  years  preceding  the  application  (which 
fact  must  be  verified  by  the  certificate  in  writing  of  the 
licensed  engineer  or  master  under  whom  the  applicant  has 
served,  said  certificate  to  be  filed  with  the  application  of  the 
candidate),  and  no  person  shall  receive  license  as  above, 
except  for  special  license,  who  is  not  able  to  determine  the 
weight  necessary  to  be  placed  on  the  lever  of  a  safety  valve 
(the  diameter  of  valve,  length  of  lever,  and  fulcrum  being 
known)  to  withstand  any  given  pressure  of  steam  in  a  boiler, 
or  who  is  not  able  to  figure  and  determine  the  strain  brought 
on  the  braces  of  a  boiler  with  given  pressure  of  steam,  the 
position  and  distance  apart  of  braces  being  known  ;  such 
knowledge  to  be  determined  by  an  examination  in  writing 
and  the  report  of  the  examination  filed  with  the  application 
in  the  office  of  the  local  inspectors,  and  no  engineer,  or 
assistant  engineer  now  holding  a  license  shall  have  the  grade 
of  the  same  raised  without  possessing  the  above  qualifi- 
cations. 

And  no  original  license  shall  be  granted  any  engineer,  01 
assistant  engineer,  who  cannot  read  and  write,  and  does  not 
understand  the  plain  rules  of  arithmetic. 

The  Secretary  of  the  Treasury  has  issued  the  following 
rules  concerning  the  examination  of  applicants  for  the  posi- 
tion of  second  assistant  engineer  in  the  United  States  revenue 
marine. 


192  IT.  S.  GOVERNMENT  RULES. 

A  candidate  for  an  appointment  as  second  assistant 
engineer  must  not  be  less  than  twenty-one  nor  more  than 
thirty  years  of  age ;  he  must  be  of  good  moral  character  and 
correct  habits ;  he  must  have  worked  not  less  than  eighteen 
months  in  a  machine  shop  and  have  had  responsible  charge 
of  a  steam  engine,  or  else  have  served  not  less  than  that 
period  in  charge  or  assisting  in  the  care  and  management 
of  the  machinery  of  a  steam  vessel  in  active  service.  Upon 
examination,  he  must  be  able  to  describe  and  sketch  all 
the  different  parts  of  the  marine  steam  engine  and 
boilers,  and  explain  their  uses  and  mechanical  operation, 
the  manner  of  putting  them  in  action,  regulating  their 
movements,  and  guarding  against  danger.  He  must  write 
a  fair  legible  hand,  be  well  acquainted  with  arithmetic, 
simple  mensuration,  English  orthography  and  composition, 
also  with  rudimentary  mechanics  and  its  practical  appli- 
cations ;  he  must  possess  some  skill  in  the  use  of  ordinary 
hand  tools,  and  have  a  fair  practical  knowledge  of  the 
nature  of  heat  and  steam,  of  the  general  lawys  in  relation 
to  the  expansion  of  steam,  of  the  uses  of  the  indicator  and 
interpretation  of  diagrams,  of  the  chemistry  of  combustion 
and  corrosion,  of  the  composition  of  sea  water  and  uses  of 
the  salinometer,  and  of  the  usual  calculations  to  determine 
loss  by  blowing,  gain  by  heat,  and  water  necessary  for  con- 
densation. 

No  person  otherwise  qualified  will  be  commissioned  as  an 
engineer  before  he  has  shown  his  ability  to  perform  duty  at 
sea  in  a  satisfactory  manner  for  a  period  of  at  least  six 
months.  This  service  may  either  antedate  or  be  acquired 
subsequent  to  an  examination. 


ENGINEERS'  EXAMINATIONS.  198 

No  person  will  be  originally  appointed  to  a  higher  grade 
than  second  assistant  engineer,  not  until  he  shall  have  passed 
a  physical  and  professional  examination.  The  physical  ex- 
amination shall  preceed  the  professional,  and  if  a  candidate 
be  rejected  physically,  he  will  not  be  examined  further.  All 
professional  examinations  will  be  competitive  in  character, 
and  applicants,  who  pass  the  minimum  standard  required  in 
several  subjects,  will  be  placed  upon  the  list  of  persons  elig- 
ible for  appointment,  in  the  order  of  the  excellence  of  their 
examinations,  respectively.  From  this  list  appointments 
will  be  made  in  regular  order,  as  vacancies  may  occur,  until 
another  examination. 

No  person  will  be  designated  for  examination  until  he  has 
filed  in  the  department  the  necessary  certificates  showing  his 
proper  qualifications  as  to  character,  habits,  and  time  or 
times  of  service,  and  the  ability  that  has  been  displayed  dur- 
ing such  service. 

Any  person  producing  a  false  certificate  of  age,  time  of 
service,  or  character,  of  making  false  statement  to  a  board 
of  examination,  will  be  dropped  immediately. 

Any  person  who,  subsequent  to  his  examination,  may  be- 
come disqualified  from  moral  considerations  will  not  be 
appointed. 


194  CITY  ORDINANCE. 


(MODEL    OF) 

CITY  ORDINANCE  RELATING  TO  ENGINEERS' 
LICENSES. 


The  following  is  given  as  a  model  of  city  regulations  re- 
quiring examinations,  and  as  nearly  all  State  and  city  laws 
are  substantially  alike,  this  may  suffice  to  indicate  the  legal 
requirements  to  be  conformed  to  by  the  applicant.  The  full 
text  of  the  law  here  given  shows  very  clearly  the  responsi- 
bility of  the  system  of  licensing  an  engineer  and  the  gravity 
with  which  it  is  regarded  by  the  public  : 

SEC.  388.  Any  person  desirous  of  being  employed  to  take 
charge  and  control  of  any  stationary  engine,  steam  boiler,  or 
other  steam  generating  apparatus  within  the  city  of  Cleve- 
land, shall  apply  to  the  Examiner  of  Engineers  for  a  blank 
application,  which  shall  have  been  prepared  by  said  Exami- 
ner of  Engineers. 

After  said  applicant  shall  have  filled  out  said  blank  appli 
cation,  and  shall  have  caused  the  same  to  be  signed  by  three 
(3)  reputable  stationary  engineers,  who  shall  have  obtained 
previously  a  license  for  said  employment,  he  shall  then  apply 
to  the  said  Examiner  of  Engineers,  to  be  examined  by  the 
Baid  Examiner  of  Engineers  touching  hia  qualifications  for 


EXAMINATIONS.  195 


such  employment,  and  if  the  said  Examiner  of  Engineers, 
after  having  made  an  examination,  shall  have  found  said 
applicant  possessed  of  the  necessary  qualifications  for  said 
employment,  he  shall  give  said  applicant  a  certificate  to  that 
effect. 

On  presentation  of  such  certificate  to  the  City  Clerk,  and 
the  payment  to  said  clerk  of  the  sum  of  fifty  (50)  cents  for 
the  first  issue  of  a  license  and  twenty-five  (25)  cents  for  each 
subsequent  issue  thereof  by  such  applicant,  the  said  clerk 
shall  issue  to  such  applicant  a  license  under  the  seal  of  said 
city,  authorizing  such  applicant  to  take  charge  and  control 
of  a  stationary  engine,  steam  boiler,  or  other  apparatus  for 
generating  steam,  for  the  period  of  one  year  from  the  date  of 
its  issue,  and  the  said  clerk  shall  pay  all  moneys  so  received 
by  him  into  the  treasury  of  said  city,  to.  the  credit  of  the 
general  fund,  provided,  however,  that  said  Examiner  of 
Engineers  shall  issue  no  such  license  to  any  applicant  who 
shall  not  have  had  one  (1)  year's  practical  experience  in  said 
employment,  except  in  private  dwelling  houses. 

SEC.  389.  It  shall  be  unlawful  for  any  person  or  persons 
to  take  charge  and  control  of  any  stationary  engine,  steam 
boiler,  or  other  apparatus  for  generating  steam,  except  in 
private  dwelling  houses,  without  having  a  license  to  do  so, 
as  provided  in  the  foregoing  section,  which  license  shall  be 
exposed  to  view  in  a  conspicuous  place  in  the  room  or  place 
containing  the  boiler,  generator,  or  engine  of  which  such 
person  is  in  charge  ;  provided,  however,  that  all  licenses 
heretofore  issued  in  pursuance  of  said  original  ordinance  shall 
continue  in  force  for  the  period  for  which  they  were  issued. 


196  CITY  ORDINANCE. 

It  shall  be  unlawful  for  any  person  or  persons,  partnership 
or  association,  company  or  corporation,  knowingly  to  employ 
or  keep  in  their  employ  for  the  purpose  of  taking  charge  and 
control  of  any  stationary  engine,  steam  boiler,  or  other 
apparatus  for  generating  steam,  except  in  private  dwelling 
houses  as  aforesaid,  any  stationary  engineer  or  other  person 
who  has  not  been  licensed  as  above  provided  and  required. 

SEC.  390.  It  is  hereby  made  the  special  duty  of  every 
police  officer  or  patrolman,  and  the  superintendent  of  police 
is  hereby  instructed  to  give  the  said  Examiner  of  Engineers 
all  possible  assistance  to  enforce  the  provisions  of  this  chapter, 
and  for  this  purpose  the  police  shall  have  authority  to  enter 
any  shop,  factory,  mill,  store,  warehouse,  hotel  or  other 
building  or  structure  in  which  a  steam  boiler  or  engine  is 
located,  and  to  demand  to  be  shown  the  license  of  the  engi- 
neer having  charge  of  said  steam  boiler  or  engine. 

SEC.  391.  Whoever  violates  any  of  the  provisions  of  this 
chapter  shall  be  subject  to  prosecution  before  the  Police 
Court  of  said  City,  and  on  conviction  thereof  be  fined  in  any 
sum  not  less  than  ten  dollars  nor  more  than  twenty  dollars 
for  the  first  offense,  and  not  less  than  twenty  dollars  nor 
more  than  fifty  dollars  for  the  second  and  each  subsequent 
offense. 


INSPECTION  OF  STEAM  BOILERS:  197 


LAWS   RELATING   TO  THE   INSPECTION  OF 
STEAM  BOILERS. 


According  to  the  laws  of  the  State,  every  owner,  agent  or 
lessee,  of  a  steam  boiler  or  boilers,  in  the  City  of  New  York, 
shall  annually  report  to  the  board  of  police,  the  location  of 
said  boiler  or  boilers,  and,  thereupon,  the  officers  in  command 
of  the  sanitary  company  shall  detail  a  practical  engineer,  who 
shall  proceed  to  inspect  such  steam  boiler  or  boilers,  and  all 
apparatus  and  appliances  connected  therewith. 

When  a  notice  is  received  from  any  owner  or  agent  that 
he  has  one  or  more  boilers  for  inspection,  a  printed  blank 
is  returned  to  him  stating  that  on.  the  day  named  therein 
the  boilers  will  be  tested,  and  he  is  asked  to  make  full  pre- 
paration for  the  inspection  by  complying  with  the  following 
rules  : 

Be  ready  to  test  at  the  above  named  time. 

Have  boiler  filled  with  water  to  safety  valve, 

Have  1%  inch  connection. 

Have  steam  gauge. 

Steam  allowed  two-thirds  amount  of  hydrostatic  pressure. 


198  INSPECTION  OF  STEAM  BOILERS. 

The  following  have  also  been  adopted  by  one  or  more 
Inspection  Companies: 

How  to  Prepare  for  Steam  Boiler  Inspection. 

1.  Haul  fires  and  all  ashes  from  furnaces  and  ash  pits. 

2.  If  time  will  permit,    allow  boiler  and  settings  to  cool 
gradually  until  there  is  no  steam  pressure,  then  allow  water 
to  run  out  of  boilers.     It  is  best  that  steam  pressure  should 
not  exceed  ten  pounds  if  used  to  blow  water  out. 

3.  Inside  of  boiler  should  be  washed  and  dried  through 
manholes  and  handholes  by  hose  service  and  wiping. 

4.  Keep  safety  valves  and  gauge  cocks  open. 

5.  Take  off  manhole  and  handhole  plates  as  soon  as  possible 
after  steam  is  out  of  boiler,  that  boiler  may  cool  inside  sufri- 
ciently  for  examination  ;   also  keep  all  doors  shut  about 
boilers  and  settings,  except  the  furnace  and  ash  pit  doors. 
Keep  dampers  open  in  pipes  and  chimneys. 

6.  Have  all  ashes  removed  from  under  boilers,  and  fire 
surfaces  of  shell  and  heacls  swept  clean. 

7.  Have  spare  packing  ready  for  use  on  manhole  and  hand- 
hole  plates,  if  the  old  packing  is  made  useless  hi  taking  off  01 
is  burned.     The  boiler  attendant  is  to  take  off  and  replace 
these  plates. 

8.  Keep  all  windows  and  doors  to  boiler  room  open,  after 
fires  are  hauled,  so  that  boilers  and  settings  may  cool  as 
quickly  as  possible. 

9.  Particular  attention  is  called  to  Rule  5,  respecting  doors 
—which  should  be  open  and  which  closed— also  arrangement 


INSPECTION  OF  STEAM  BOILERS.  l»i> 

of  damper.  The  importance  of  cooling  the  inside  of  the 
boiler  by  removal  of  manhole  and  handhole  plates  at  the 
same  time  the  outside  is  cooling,  is  in  equalizing  the  process 
of  contraction. 

Issuing  Certificates. 

These  conditions  having  been  complied  with,  the  boiler  is 
thoroughly  tested,  and  if  it  is  deemed  capable  of  doing  the 
"work  required  of  it,  a  number  by  "which  it  shall  hereafter  be 
known  and  designated  is  placed  upon  it  in  accordance  with 
the  city  ordinance  :  Failure  to  comply  with  this  provision  is 
punishable  by  a  fine  of  $25.  A  certificate  of  inspection  is 
then  given  to  the  owner,  for  which  a  fee  of  $2  is  paid. 

This  certificate  sets  forth  that  on  the  day  named  the  boiler 
therein  described  was  subject  to  a  hydrostatic  pressure  of  a 
certain  number  of  pounds  to  the  square  inch.  The  certificate 
tells  where  the  boiler  was  built,  its  style  or  character  and 
' '  now  appears  to  be  in  good  condition  and  safe  to  sustain  a 

working  pressure  of to  the  square  inch.     The  safety 

valve  has  been  set  to  said  pressure."  A  duplicate  of  this 
certificate  is  posted  in  full  view  in  the  boiler  room.  In  case 
the  boiler  does  not  stand  the  test  to  which  it  is  subject,  it 
must  be  immediately  repaired  and  put  in  good  working  order 
before  a  certificate  will  be  issued. 

Applicants  for  licenses  are  very  liable  to  be  asked — to  test 
their  experience  in  and  around  steam  boilers — some  questions 
relating  to  their  inspection  ;  hence  the  value  of  these  extracts 
upon  the  subject. 


200  C&IEF  INSPECTOR'S  REPORTS. 

IMPORTANT. 

The  following  ten  pages  are  undoubtedly  the  most, 
valuable  and  instructive  of  any  same  number  of  pages 
in  this  volume.  They  indicate  the  path  of  advance  ir 
granting  licenses  for  the  future,  and,  with  admirable 
modesty,  the  great  benefits  which  have  accrued  from  a 
wise  and  faithful  administration  of  public  law,  con 
trolling  engineers'  examinations  and  the  granting  of 
licenses.  It  will  be  happier  times  when  the  whole 
country  is  equally  guarded  and  protected. 


STEAM  BOILER  INSPECTION  AND   CERTIFI- 
CATION OF  ENGINEERS. 

BY  THE  SUPERINTENDENT,   DEPARTMENT    BOILER    INSPECTION 
BROOKLYN,   N.   Y. 


(Extract.) 

In  tue  city  of  Brooklyn  the  inspection  of  boilers  is  made 
by  a  corps  of  six  inspectors.  The  hydrostatic  test  is  applied, 
and  wherever  deemed  necessary,  a  hammer  test  is  added. 
Whenever  defects  are  ascertained,  they  are  caused  to  be 
remedied  or  the  boiler  condemned. 

The  inspection  of  steam  boilers  and  the  certification  of 
engineers  to  manage  and  care  for  the  same  are  subjects  to 
which  much  thought  has  been  given  by  the  best  engineers  of 
the  country.  From  the  inception  of  the  general  idea  of 
official  boiler  inspection  to  the  present  date,  great  strides 


CERTIFICATION  OF  &NQINEE&&  201 

have  been  made  by  both  national,  state  and  municipal  gov- 
ernments in  bringing  the  system  to  perfection,  and  to  throw 
around  boilers  under  their  supervision  every  safeguard  that 
human  ingenuity  could  devise. 

The  United  States  government,  through  its  able  corps  of 
naval  engineers,  has  done  much  to  advance  the  interests  of 
those  engaged  in  this  work,  having  systematized  the  work  so 
that  the  best  possible  results  are  attained  with  the  material 
at  hand.  The  individual  states  are  also  gradually  falling 
into  line  and  are  enacting  laws  providing  for  the  needed 
inspection. 

In  the  cities  of  New  York  and  Brooklyn  the  laws  govern- 
ing boiler  inspection  are  similar  in  general  principle,  while 
differing  in  some  of  the  particulars.  In  both  cities  the 
bureaus  of  inspection  are  a  branch  of  the  police  dapartment, 
responsible  to  the  commissioner  or  commissioners  of  police. 
In  the  former  city,  officers  are  detailed  for  this  work  from 
the  police  force,  after  having  given  satisfactory  evidence  of 
their  qualification  for  this  duty,  and  are  under  a  command- 
ing officer  of  experience  and  discretion. 

In  the  city  of  Brooklyn,  while  the  inspectors  are  not 
members  of  the  force,  they  are  entitled  to  all  the  privileges 
and  subject  to  the  same  discipline.  The  superintendent  of 
steam  boilers  is  a  position  provided  for  by  statute,  the  quali- 
fications for  which  are  set  forth  explicitly,  and  the  duties  and 
authority  expressed  in  such  laws.  The  examination  and 
grading  of  engineers  is  discretionary  with  him,  and  the 
steam  plants  in  the  city  are  classified  and  recorded  in  his 
office.  The  aim  and  desire  of  the  department  is  to  assist  and 


CERTIFICATION  OF  ENGINEERS. 


encourage  the  best  skill  among  our  engineers,  thereby  aiding 
the  worthy  and  deserving  men,  as  well  as  to  provide  for 
steam  users  the  best  material  for  the  management  of  their 
several  steam  plants. 

The  Association  of  Boiler  Inspectors  of  the  United  State? 
and  Canada,  following  the  example  set  by  the  United  States 
inspectors,  hold  annual  meetings  for  the  interchange  of  views 
and  opinions  as  to  the  best  method  of  boiler  inspection.  They 
have  adopted  rules  which,  while  not  legally  binding  upon  its 
members  as  are  the  rules  of  the  latter  body,  yet  place  a  moral 
obligation  for  the  carrying  out  of  the  same. 

It  is  our  proud  privilege  to  be  able  to  say  that  since  the 
institution  of  the  inspection  of  steam  boilers  in  this  city, 
there  has  been  no  explosion  of  a  steam  boiler  that  had  prev- 
iously been  inspected  by  the  department. 

The  inspectors  are  always  on  the  alert,  and  arrests  are  fre- 
quently made  for  violation  of  our  laws,  and  the  courts  by 
their  actions  sustain  and  strengthen  the  hands  of  the  depart- 
ment in  enforcing  the  law. 

The  engineers  of  this  city  are  of  great  assistance  to  the 
department  in  the  care  of  their  several  plants,  and  are  ever 
ready  to  assist  the  department  in  its  work.  The  steam  users 
as  well  recognize  the  importance  of  the  work,  and  it  is  the 
desire  of  the  department  while  enforcing  the  law  to  conserve 
their  interests  wherever  practicable.  There  are  some  imper- 
fections in  our  laws  that  might  be  corrected,  and  some  action 
will  be  taken  in  that  direction  to  the  betterment  of  the 
department  and  the  perfection  of  the  work. 

JAN'Y,  1895.  W   A,  POWERS, 


CHIEF  INSPECTOR'S  REPORTS.  206 


SPECIAL  REPORT 

OF    THE 

NEW  YORK  CITY  STEAM  BOILER  INSPECTION  AND  ENGINEERS' 
BUREAU,  JAN.  1,  1895, 

ON 

BOILER  INSPECTION  AND  THE  LicENScra  OF  ENGINEERS. 


in  the  last  annual  report  from  this  bureau  the  inadequacy 
of  the  present  method  of  boiler  inspection  was  commented 

There  are  but  few  engineers  in  New  York  City  who  have  not  met 
Sergeant  Washington  Mullin,  Chief  of  the  Boiler  Inspection  and 
Engineer's  Bureau,  of  New  York  City.  Thousands  of  engineers  know 
him  at  sight.  For  the  benefit  of  those  who  have  not  had  the  pleasure 
of  meeting  him  we  herewith  present  a  brief  sketch  of  his  active  life : 

Officer  Mullin  was  born  in  the  City  of  Philadelphia,  Sept.  29th, 
1837.  His  parents  removed  to  New  York  City  when  he  was  but  eight 
years  of  age,  and  he  attended  the  public  schools  until  he  had  reached 
his  sixteenth  year,  when  he  was  apprenticed  in  the  engine  and 
machine  works  of  Abraham  Van  Ness,  where  he  was  working  at  the 
breaking  out  of  the  war.  Young  Mullin  was  among  the  first  to 
respond  to  his  country's  call,  and  assisted  in  organizing  Company  "E,w 
73d  N.  Y.  Volunteers.  He  participated  in  all  of  the  engagements  iffi 
which  his  brigade  took  part ;  was  promoted  to  first  lieutenant,  and 
honorably  discharged  September,  1864 ;  was  appointed  to  the  Police 
Department,  New  York  City,  September,  1864,  promoted  to  roundsman 
Oct.,  1865,  to  sergeant  1868,  and  subsequently  assigned  as  Chief  of  the 
Boiler  Inspection  and  Engineer's  Bureau,  February,  1882. 

Schooled  as  a  soldier,  he  is  a  strict  disciplinarian ;  uses  discretion 
in  the  examination  of  the  many  thousand  engineers  who  come  before 
him  annually  to  pass  the  examination  preparatory  to  taking  out  the 
engineer's  license  required  by  law;  never  discriminates,  treats  all 
applicants  alike,  shows  no  favoritism,  and  the  engineer  who  obtains  a 
license  must  pass  the  necessary  examination  in  a  satisfactory  manner, 
proving  his  ability  to  take  charge  of  and  operate  a  steam  plant.  The 
competent  have  nothing  to  fear  in  Sergeant  Mullin— the  ignorant* 
incompetent  and  intemperate  are  always  rejected. 

The  Engineer's  List,  Jan.  W. 


#04  SPECIAL  REPORT— IMPORTANT. 

upon,  and  recommendations  made  for  a  change  in  the  laws 
to  improve  the  system,  to  the  end  that  the  protection  to  life 
and  property  be  made  more  secure,  and  the  dangers  from 
such  casualties  as  boiler  explosions  reduced  to  a  minimum. 

While  there  were  several  bills  presented  to  the  last  Legisla 
tore,  touching  upon  the  matter  of  boiler  inspections  and 
licensing  of  engineers,  none  seemed  to  meet  with  approval 
and  all  failed  of  passage. 

Therefore,  it  is  again  respectfully  submitted  that,  in  con- 
sequence of  the  danger  to  life  and  property,  attendant  upon 
the  operation  of  steam  boilers,  it  would  seem  that  no  difficulty 
should  be  encountered  in  the  endeavors  made  to  have  them 
legally  regulated  as  to  their  proper  and  careful  construction 
and  inspection,  as  well  as  to  the  licensing  of  those  who  are 
to  have  charge  and  operate  them,  more  especially  in  locali- 
ties which  are  thickly  populated,  and  where  an  explosion  of 
a  steam  boiler  means  dire  disaster. 

As  a  matter  of  comparison  between  the  different  places  in 
the  United  States,  where  there  are  inspection  laws  and  where 
no  legal  supervision  exists,  it  will  be  noted  that  the  casual- 
ties resulting  from  boiler  explosions  are  as  one  to  a  hundred. 
If  the  importance  of  this  matter  was  properly  and  intelli- 
gently impressed  upon  the  consideration  of  those  selected 
to  make  the  laws,  and  more  stringent  safeguards  were  drawn 
around  the  laws  and  ordinances  now  in  force,  a  much  greater 
percentage  would  be  shown  in  favor  of  legal  supervision. 

The  boiler- inspection  laws  now  in  operation  in  the  cities 
of  New  York  and  Brooklyn,  as  far  as  the  particular  method 
of  inspection  is  concerned,  are  the  same  as  those  existing  in 


SPECIAL  REPORT-IMPORTANT.  205 

1862,  when  not  more  than  2,000  steam  boilers  were  operated 
hi  the  then  metropolitan  district,  comprising  the  counties  of 
New  York,  Kings,  Richmond  and  parts  of  Queens  and  West- 
Chester,  while  now  there  are  upward  of  8,000  boilers  in  use 
in  the  City  of  New  York  alone. 

At  the  time  mentioned,  and  for  some  years  after,  the  aver- 
age pressure  used  to  operate  steam  boilers  was  about  fifty 
pounds  to  the  square  inch,  whereas,  at  present,  owing  to  the 
advancement  and  improvements  made  in  machinery  and 
other  devices  necessary  for  steam  to  operate  have  been  so 
great  that  the  average  pressure  carried  will  equal  100  pounds 
to  the  square  inch,  and  yet,  withal,  no  legal  advancement 
has  been  made  in  the  matters  regulating  the  testing  and  in- 
spection of  boilers.  To  be  sure,  reputable  manufacturers 
and  builders  of  steam  boilers  take  the  necessary  precaution 
in  building  boilers  required  to  withstand  this  extra  demand 
for  increased  pressure,  but  it  is  to  guard  against  that  class  of 
firms  who  construct  cheap  work,  taking  chances  on  the 
safety  and  security  of  the  boilers  they  make,  that  more  rigid 
laws  should  be  enacted. 

Such  laws  should  provide  that  every  maker  of  a  boiler 
should  issue  or  give  a  certificate,  setting  forth  the  quality 
and  thickness  of  the  material  used,  its  guaranteed  tensile 
strength  and  ductility,  the  pressure  per  square  inch  the  boiler 
is  designed  to  carry,  and  every  particular  concerning  its  con- 
struction, and  that  in  the  absence  of  such  certificate  the  ten- 
sile strength  of  the  material  should  be  calculated  at  40,000 
Ibs.  for  iron  and  50,000  Ibs.  for  s-teel  plates,  when  determin- 
ing the  safe  working  pressure. 


206  SPECIAL  REPORT— IMPORTANT. 

The  strength  and  security  of  a  boiler  should  be  determined 
by  a  series  of  calculations,  based  upon  established  rules,  upon 
its  various  parts,  and,  when  the  workmanship  and  material 
is  found  to  be  of  good  quality,  a  factor  of  five  should  be  the 
standard  used  to  determine  the  safe  working  pressure  to  be 
allowed. 

But,  in  the  matter  of  inferior  workmanship  or  inferior 
material,  authority  should  be  given  the  inspector  to  either 
condemn  the  boiler  or  increase  the  factor  to  a  degree  that 
would  insure  the  utmost  safety  in  the  operation  of  the  boiler. 
Then,  again,  every  boiler  should  be  subjected  to  a  hydrostatic 
test  before  put  in  actual  operation,  such  a  test  to  be  made  at 
least  once  every  year  thereafter,  and  in  the  following 
manner: 

The  boiler  to  be  filled  entirely  with  water,  a  fire  lighted  in 
the  furnace,  and  the  temperature  of  water  brought  to  at 
least  150  degrees  of  Fahrenheit,  when  the  boiler  should  be 
subjected  to  a  hydrostatic  pressure  of  one  and  one-half  tunes 
the  steam  or  working  pressure  to  be  allowed  per  square  inch. 
The  inspector,  after  applying  the  hydrostatic  test,  should  go 
inside  the  boiler  and  make  a  thorough  examination  of  every 
part  of  the  same,  and,  if  the  test  is  not  satisfactory,  the  de- 
fects should  be  made  good,  and  the  boiler  re-tested. 

In  water-tube  boilers,  constructed  to  carry  150  Ibs.  or  more, 
where  the  factor  of  safety  is  generally  above  seven,  the 
pressure  should  be  one  and  one-quarter  times  the  working 
pressure  to  be  allowed,  for  the  reason  that  pressure  above 
225  Ibs.  will  rupture  calking  in  longitudinal  seams  of  steam 
drums. 


SPECIAL  REPOBT-IMPOHTANT.  207 

In  determining  the  working  pressure  for  boilers  that  have 
been  several  years  in  use,  the  inspector  should  take  into  con- 
sideration the  age  and  condition  under  which  it  has  been 
operated,  as  well  as  the  thickness,  original  strength,  efficiency 
of  riveted  joints,  etc.,  and  make  calculation  between  what 
was  its  safe  working  pressure  when  new,  and  the  pressure 
now  desired,  and  he  should  make  due  allowance  for  deterio- 
ration, and,  if  necessary,  drill  holes  to  properly  determine  its 
thickness. 

All  boilers  should  have  a  composition  valve  or  cock  placed 
in  the  feed  line,  between  the  check  valve  and  the  boiler,  so 
as  to  permit  of  overhauling  the  check  when  steam  is  up,  if 
necessary.  All  pipe  connections  of  over  one  inch  internal 
diameter  should  be  attached  to  the  boiler  by  a  flanged  joint, 
riveted  or  bolted.  Each  boiler  should  have  three  gauge  cocks 
and  a  water  glass,  and  the  gauge  cocks  and  water  column 
should  be  connected  directly  to  the  boiler  with  at  least  one- 
inch  pipe,  the  lower  water  pipe  to  be  tapped  near  the  bottom 
of  the  boiler,  and  the  upper  steam  pipe  connected  at  the  top 
of  the  boiler,  and  as  far  away  from  where  the  main  steam 
pipe  is  connected  as  is  practical. 

No  other  connection  should  be  allowed  to  be  taken  from  it. 
A  blow  cock  should  be  placed  at  the  bottom  of  the  lower 
water  pipe.  The  bottom  gauge  cock  should  be  placed  at  least 
two  inches  above  the  highest  heating  surface,  and  the  other 
cock  placed  in  proper  proportions,  so  as  not  to  unduly  reduce 
the  intended  steam  space.  * 

Each  boiler  should  have  a  steam  gauge  that  would  cor- 
rectly indicate  one-and-a-half  times  the  working  pressure 


208  SPECIAL 


allowed,  and  one  safety  valve  of  sufficient  capacity,  when 
open,  to  carry  off  all  the  steam  the  boiler  could  generate  with 
all  the  other  valves  closed. 

The  blow-off  pipe  on  horizontal  tubular  boilers,  when  at- 
tached to  the  back  connection  or  combustion  chamber,  should 
be  of  ample  size,  but  not  to  exceed  two  inches  internal  diam 
eter,  and  should  be  of  extra  heavy  pipe,  with  malleable  fit- 
tings, and  protected  from  the  intense  heat  by  a  metal  sleeve 
or  other  covering,  and,  in  the  absence  of  such  covering,  there 
should  be  a  circulating  pipe  connected  with  the  upper  part 
of  the  boiler  to  give  good  circulation  and  eliminate  the 
danger  attending  the  dead  end  between  the  blow  cock  and 

boiler.     There  should  also  be  a  surface  blow-off. 

• 
All  high  pressure  boilers  of  the  vertical  or  locomotive  style 

should  have  a  fusible  plug  placed  in  the  crown  sheet. 

Boilers  should  have  two  ways  of  feeding  —  by  a  steam  pump 
and  by  an  injector;  pumps  to  be  used  only  when  hot  water 
is  available  or  the  injector  out  of  order.  When  two  or  more 
boilers  are  connected,  the  inspectors  should  give  particular 
attention  to  the  connection  in  the  main  steam  pipe,  and  see 
that  due  allowance  is  made  for  expansion. 

That  a  proper  record  of  each  boiler  may  be  kept,  and  that 
it  could  be  at  all  times  easily  identified,  a  plate,  bearing  the 
official  record  number  of  the  boiler,  should  be  securely  and 
permanently  fastened  to  the  boiler  in  a  conspicuous  place. 

It  should  be  made  the  duty  of  engineers  in  charge  of  steam 
boilers,  to  blow,  or  cause  to  blow,  at  least  once  each  day,  the 
safety  valve  to  insure  its  readiness  for  use,  and  should  a 


SPECIAL  REPORT— IMPORTANT.  209 


safety  valve  be  found,  at  the  annual  inspection,  to  have  been 
tampered  with  or  out  of  order,  the  certificate  of  the  person 
in  charge  should  be  suspended  or  revoked. 

Provision  should  also  be  made  that  would  require  an  engi- 
neer to  go  inside  his  boiler,  at  least  once  in  three  months,  to 
cleanse  the  same,  and  see  that  no  accumulation  of  scale  or 
corrosion  had  taken  place.  By  this  means  the  property  of 
his  employer  will  be  protected,  the  life  of  the  boiler  pro- 
longed, and  the  loss  to  life  and  property  averted. 

These  are  mentioned  as  some  of  the  provisions  that  should 
be  embodied  in  a  law  which,  when  drafted,  would  cover  the 
necessary  requirements  more  in  detail,  and  which  would 
surely  meet  the  approval,  and  ultimately  result  to  the  bene- 
fit, of  owner,  steam  user,  engineer,  and  everybody  in  any 
way  concerned  or  interested  in  the  use  of  steam,  or  the  safety 
to  life  and  property.  Respectfully  submitted, 

WASHINGTON  MULUN. 


210  HA  WKIN&  AIDS. 


FOR 


Hawkins'  Aids  to  Engineers'  Examinations. 


Absolute  pressure  of  steam 62 

Absorber,  the ..  146 

Absorption  (the)  system  defined 146 

Action  of  injector 119 

Action  of  pump  described 106 

Addition  of  decimals 168 

Advantages  of  compounding 80 

Agitator  (the)  use  of 147 

Air  for  combustion ;  how  supplied 49 

Hot;  not  good  t9  supply  furnace 49 

Machines  described 149 

Objections  to 149 

Standard  for  specific  gravity 134 

"Weight  of',  under  pressure  in  a  boiler. 61 

Alloy,  definition  of 26 

Ammonia,  advantages  of. 143 

Anhydrous 143 

Aqua. i. •>. .     ...............  147 

Cycle  of  compression,  condensation,  expansion 147-148 

Pump  defined 146 

Receiver 146 

Appliances  for  the  operation  of  a  steam  boiler 8? 

Aqua  ammonia  defined *  147 

Area  of  pump  pistons 113 

Arithmetic,  summary  of • 

Arithmetical  signs 165 

Calculations,  unit  of 154 

Progression 172 

Automatic  cut-off  of  engines 68 


A  well  arranged  Index  doubles  the  value  of  a  scientific  and 
mechanical  work  ;  it  is  like  a  guide  post  to  a  traveller  journeying 
through  an  unknown  country.  A  good  index  tells  very  quickly  the 
entire  contents  of  a  book — it  not  only  gives  the  page  where  particular 
information  is  to  be  found,  but  it  forcibly  indicates  to  the  student 
those  items  of  necessary  knowledge  of  which  he  is  ignorant  and 
which  it  is  best  for  him  to  "study  up.1' 


IMJJCLX.  811 

Back  press-lire 74 

Valve 85 

Ball  valve 85 

Baseline 122 

Bearing  bars.... 58 

Bismuth,  specific  heat  of 153 

Bituminous  coal,  how  to  fire 43 

Combustion  of 48 

Lbs.  of  water  evaporated  from  and  at  212° 50 

Units  of  heat  of  combustion 50 

Boiler  braces  and  stays 29 

Fittings 82 

Materials 23 

Plates,  qualifications  for 24 

Plate,  thinnest  it  is  desirable  to  use 53 

Rule  to  find  capacit  y  of 116 

Steam,  descri ption ....  21 

Tests. 140 

Tubes,  how  to  estimate  the  diameter  of 86 

Boiling,  irregularity  of 140 

Process  of 63 

Braces, arrangement  of ,  in  aboiler 31 

How  best  to  make  repairs 33 

Materials  of  which  made 31 

Questions  and  answers  relating  to 29 

Stays 29 

Stress  allowed  on 32 

Brass,  specific  gravity  of 137 

BricK,  specific  gravity  of 137 

Brine  system  of  refrigeration  144 

System,  how  the  briue is  circulated ;.,  .  145 

Tank,  how  arranged 144 

Brush  (in  electricity)  defined 132 

Brushes;  important  rule  regarding 132 

Butt-joint,  description 66 

Calculations  for  safety  valve ;..  92-97 

Of  expansion  and  contraction  of  steam  boilers 28 

Of  strength  of  seam  of  steam  boiler 56 

Power  of  steam  engine 79 

The  mean  effective  pressure 79 

Capacity  of  boiler ;  rulefor 116 

Capacity,  safe  rule  for  pump, 109 

Of  steam  pump 113 

Of  water  cylinder 113 

Carbon,  units  of  heat  of  combustion 50 

Lbs.  of  water  evaporation  at  212° 50 

Card,  Indicator 121 

Caulking,  definition  of 63 

Centigrade  thermometer,  description 152 

Certificates,  issuing 199 

(new)granted  in N.  Y ix 

(refused)  in  N.  Y.  City ix 

Renewed  in  N.  Y.  City ix 

Charcoal,  specific  gravity  of 137 

Check .valve 86 

Chemical  law  on  which  the  absorption  system  is  based 147 

Chemical  refrigeration 148 

Chief  engineer,  rank  of 187 

Circulation  of  water  in  boiler,  cause  of 46 

C.'ty  Ordinance  relating  to  engineers*  licenses,  (model  of; «  194 


21S  OAWKLPfST  AUKS. 


Classes  of  engines '. 68 

Of  compound  engines 80 

Of  levers 93 

Classification  of  knowledge  the  key  to  success 17 

Of  steam  engines 64-65 

Cleaning  a  fire,  way  of „..  43 

Clearance  defined 70 

Coal,  bituminous,  how  to  fire 43 

Bituminous,  Ibs.  of  water  evaporated  from  and  at  212° 50 

Bituminous,  units  of  heat  of  combustion 50 

Combustion  of 48 

Hard,  units  of  heat  of  combustion 50 

Hard,  Ibs.  of  water  evaporated  from  and  a  1 212° 50 

Hard,  how  to  fire 43 

How  much  *'  cold  "  in  a  Ib.  of 144 

In  furnace ;  thickness  of  bed  of 43 

Progress  in  economical  use 66 

Specific  heat  of ,..'.. 153 

Specific  gravityof 137 

Cock;  definitionof  a 84 

Gauge 42 

Cohesion  defined 135 

Of  water 63 

Coke,  burns  after  gas  in  combustion 48 

Lbs.  of  water  evaporated  from  and  at  212° 50 

Total  units  of  heat  of  combustion 50 

Cold,  effect  on  iron 32 

How  much  iu  alb.  of  coal 144 

Cold-short  iron  or  steel ...  30 

Combustible,  definition 51 

Combustion  of  bituminous  coal 48 

Chamber,  essentials  of 51 

Process  Of 48,51 

Table  of  heat  of 50 

Commutator  defined 133 

Composition  of  water 116 

Compound  engines,  description  of 80 

Rule  to  calculate  horse  power ....  80 

Compounding,  ad  vantages  of 80 

Compressor,  double-acting 149 

Condenser  defined 143 

Submerged  and  open  air 146 

Condensing  engines    64 

How  to  manage 78 

Conductor;  definition  of 128 

Varietiesof. ...  ..  129 

Conservation  of  energy 150 

Constituents  of  steam 60 

Construction  of  a  dynamo 130 

Of  steam  boilers 53 

Contraction  and  expansion  of  steel  boilers 83 

Cooling  tank  (the* 146 

Copper,  specific  heat  of 153 

Specific  gravity  of 137 

CoriissfThe)  Engine 67 

Corliss  engine  valves ;  how  to  set 174 

Corliss  valve,  illustration 6 

Covering  steam  pipe ;  importance  of 158 

Crank;  object  of  the 72 

Crowfoot  brace..., 80 

Crushing  strength  defined-  . ..........».....••.••••*•••»•••••••«••.  135 


INDEX.  918 

Cycle  or  circle  of  ammonia 147 

Cylinder;  deiinition  of 75 

Condensation,  how  to  remedy 77 

Clearancein 70 

Water  in,  effect  of 74 

Dead  centers  of  engines . 88 

How  to  pass,  without  jarring 88 

Dead  steam 59 

Decimals 166 

Dedication  of  the  work iii 

Defective  diagram 125 

Diagram,  defective 125 

Diagram  of  an  indicator 123 

Results  obtained  by  an  indicator  diagram 123 

Diameter  of  different  tubes ;  how  to  ascertain 86 

Difference  between  pump  and  injector 117 

Between  steel  and  iron 26 

Direct" acting  duplex  pump 112 

Direct  acting  steam  pump 

Direct  expansion  system 144-145 

Division  of  decimals 169 

Double  acting  compressor,  denned 149 

Double  acting  engines 65 

Double  acting  pump *  107 

Double  injectors 119 

Double  riveting 52 

Drain  cocks ;  how  to  manage » 78 

Drainage  of  pipes •  •  86 

Dry  steam 59 

Dry  steam  as  a  conductor. 104 

Ductility,  definition  of 23 

Duplex  pumps ;  direct  acting 112 

Duplex  pump ;  rule  for  setting , 179 

Duplicate  parts,  advantage  of  keeping  on  hand 82 

Durability  oi  engines £9 

Duties  of  a  slide-valve ; 73 

Dynamos,  construction  of 130 

Dynamo-electric  machine 130 

Dynamo ;  general  construction 130 

Dynamo  "  trouble," 133 

Eccentric :  how  to  adjust  on  a  new  shaft. 75 

Economy  in  production  of  steam 66 

Ofsteam 69 

Effect  of  water  in  cylinder 74 

Effect  on  particles  of  water  changing  it  to  steam 63 

Effective  Horse  Power  (E.  H.  P.) 138 

Elastic  limit,  definition  of 22 

Electric  current 127 

Electricity,  and  electric  machines ;  questions  and  answers  relat- 
ing to 126 

For  engineers 126 

Kindsof 128 

Electric  machines  and  circuits ;  how  to  keep  in  order 130 

Electro  magnet 131 

Elementary  questions  by  1  he  examining  engineer 180 

Elongation  of  iron  and  steel 52 

Of  metals 80 

Energy,  definition  of 153 

Engine  (Steam) 64 

Engine  and  boiler  fittings 82 

Condensing,  how  to  manage *  78 


i{14  HAWKINS*  AIDS. 


Engine,  Compound 74 

Difference  in  high  and  low  pressure 74 

Fixtures ;  questions  and  answers  relating  to 83 

Ifow  to  pas?  dead  center 88 

Slide  valve,  how  to  reverse  motion 75 

Taking  charge  of  new 88 

What  to  do  before  starting  an 78 

Engines,  automatic 68 

Clearance 70 

High  speeds 67 

Pumping 112 

Simplicity  desirable 68 

The  Corliss 67 

Throttling 68 

Engineers'  examinations,  N.  Y.  City ix 

Engineers'  certificates  renewed  in.  N.  Y.  City ix 

Engineers'  licenses ;  City  Ordin ance  relati  •  g  to 194 

Brooklyn,  N.  Y.,  official  report 200 

Officialreport 2<)3 

Engineers'  licenses  '•  accessary  qualifications  to  secure 13 

Equalizer  (the) .- 146 

Evaporatipn  per  Ib.  coal  in  ordinary  boiler 40 

Examination,  conducted  by  oneself 180 

Examinations  of  applicants  for  U.  8.  Government  engineers' 

licenses  ;  Rules  for. 186 

Example  for  ruJe  11  H.  marine  examination 185 

Exhaust-lap 71 

Exhaust  line 121 

Ports,  definition 76 

Steam,  in ject9r 119 

Expansion  engines,  principles  on  which  they  work 81 

Expansion  and  contraction  of  boilers 27 

How  to  avoid  dangers  of 28 

<Tixed  and  movable 72 

Of  steam  \  gain  in  the  use  of. 104 

Of  water  in  changing  to  steam 60 

Of  gteam,  according  to  pressure 60 

Expansion  line 121 

Expansion  valve 147 

Explosions,  great  cause  of  boiler 41 

Extract  from  N.  Y.  Laws  relating  to  qualifications 14 

Factor  of  safety  for  fittings 86 

In  figuring  strength  of  steam  boiler 57 

Fahrenheit's  thermometer,  description 152 

Feed  pump;  design  of  a 114 

Fire  surface  of  a  boiler ;  how  proportioned 157 

Firing ;  Rules  for 45 

First  assistant  engineers 188 

Fittings  for  engines  and  boilers 82 

Flange;  definition  of  boiler 53 

"Flashing";  because  of 132 

Flow  of  electric  currents 128 

Flywheel 88 

Fly  wheel,  not  needed  in  locomotive  and  marine  engines 88 

Foot-pounds  in  a  H.  P 138 

Force  of  expansion;  how  to  calculate 28 

Freezing  point    . 153 

Freezingtank  (the) 146 

Fullering  defined 53 

Fulton,  Robt cutiv 

Furnace,  supply  of  air  to 49 


INDEX.  215 

Gas  (coal)  Ibs.  of  water  evaporated  from  and  at  213° • 50 

Gas  (coal)  units  of  heat  of  combustion 50 

Gas,  first  burns  in  combustion 48 

Gas,  how  ignited 48 

Generator,  in  ice  making. 146 

Gland ;  definition „.  76 

Glass,  specific  gravity  of 137 

(7 lobe  valves ;  to  attach 84 

Gold,  specific  gravity  of , 137 

Government  (U.  ».)  rules  tor  examination  of  applicants  for  engi- 

r. eers*  licenses 186 

Ganges,  water 42 

Grate  bars 58 

Gravity ;  questions  a  nd  answers  relating  to 134 

Specific  table.... 137 

Gusset-stay 30 

Gusset-stays,  riveting  of  , 84 

Hammer-test  of  steam  boilers 48 

Hard  coal,  how  to  fire 43 

Hard,  or  anthracite  coal — total  units  of  heat  of  combustion 50 

Heads  of  boilers,  dimensions 55 

Head-to-head  brace 80 

Heat  and  work 150 

Cause  of  water  circulation.... r ,  46 

Effect  of,  on  strength  of  boilers 58 

Effect  on  iron 21 

Mechanical  equivalent  of...., 151 

Of  combustion,  table  of 50 

Of  saturated  steam 101 

Specific 153 

The  best  non-conductor  of 159 

Transferable 151 

Unitof 154 

Heating  and  ventilation 155 

Heating  surface  of  steam  boilers,  efficiency  of 88 

High  and  low  pressure  engines,  difference 74 

High  and  low  pressure  steam ..  .  62 

High  pressure  engines 64 

Homogeneous,  definition 24 

Horizontal  tubular,  advantages  of 88 

Horsepower;  how  to  determine 79 

(He      P.) 138 

Indicated  and  effective 125 

Necessary  for  given  pressure 113 

Of  steam  boiler,  rule 138 

Shown  by  diagram 124 

Hot-short  iron  or  steel 24 

Hotwater?    Willpump  lift 109 

Hydraulic  test  of  steam  boilers,, 54 

Hydrogen  in  steam o 60 

Total  units  of  combustion. t,..  60 

Hydrometer;  definition  of 136 

Ice  making,  description 141 

Imperfect  insulation;  effect  of 131 

Indicated  horse  power  (I.  H.  P.) 138 

Indicator  card 121 

How  to  measure  easily 123 

Indicator  diagram « 123 

General  principles  of 120 

Questions  and  answers  relating  to 120 

Initial  pressureof  steam 68 


816  HAWKINS* 


Injectojror  Inspirator,  defined H7 

Exhaust  steam H9 

How  to  connect ••••••• 118 

Injector;  Modeof  working ,, 319 

And  pump;  difference  between.... 117 

Inspection  of  steam  boilers ;  laws  relating  to  the 197 

Sup't  Parker's  report «OU 

Insulation;  definition  of 131 

Jseceissityof  careful 130 

Iron,  definition 25 

Elongation  of 24 

Difference  between,  and  steel 25 

Hot-short  and  cold-short 24 

Specific  heat  of. 


Specific  gravity  of. 
Tensile  strength 


Jaw-brace   ... 80 

Kinds  of  electricity 128 

Knowledge  (classification  of)  the  key  to  success. 17 

Lap-joint^  description „ 66 

Lap— why  given  a  valve 72 

Latent  heat  of  steam '     Id.? 

Law  of  expansion  of  steam  under  pressure 61 

Laws  relating  to  the  inspection  of  steam  boilers 197 

Laws  relating  to  ventilation,  air,  etc 156 

**  Lead",  how  to  set  valve  for 71 

Lead,  specific  heat  of 158 

Specific  gravity  of 137 

Leakage  around  boiler  tubes,  cause  of 86 

Leaky  piston;  totestfor 77 

Pumps Ill 

Slide  valve;  totestfor 77 

Length  of  lever  for  valve  to  blow  at  given  pressure 188 

Lever;  how  to  calculate  power  of « 92-97 

Kinds  and  classes  of 93 

Licensing  of  engineers;  N.  Y.  City  report 203 

Brooklyn,  N.  Y.,  practice 

License,  necessary  qualifications  to  secure 18 

Licenses  granted,  renewed  and  rejected  (official  report) ix 

Lift  of  valves 116 

Limit  of  lift  to  a  pump 108 

Live  steam 69 

Location  of  safety  valve. - 90 

Locomotive  boilers,  peculiarity  of .^ 40 

Engines 65 

How  to  fire  a 44 

Loss  in  water  for  engine ;  provision  for 115 

Low  pressure  steam 62 

Lowwater:  what  is  to  be  done  in  case  of 42 

Lugs;  definition  of 64 

Magnet;  electro... 13 

Permanent. 13 

Malleable  metal 23 

Marine  boilers ;  peculiarity  of 40 

Engines 65 

Marine  engineers;  regulations  relating  to 

Mean  effective  pressure ;  how  to  find 

Table 

Measures  and  weights 154 

Mechanical  equivalent  of  heat •  151 

Refrigeration. .........  •••••••••»••««•«««••«•••«•••<«••»  149 


INDEX.  an 

Mercury;  specific  gravity  of 137 

Specific  heat  of 153 

Mullins,  Washington ;  sketch  of  life 203 

Multiplication  of  decimals 169 

New  steam  plant ;  first  thin?  to  be  done  in  taking  charge 158 

Nominal  horse  power  (N.  H.  P.) 138 

Non-condensing  engines 64 

Non-conductors. 129 

Non-conductor  of  heat ;  the  best 159 

North  pole  of  electro  magnet 131 

"  North  West "  steamer,  description  of  engines 81 

Number  of  indicator  spring 123 

N.  Y.  City  Laws,  extract  relating  to  qualifications It 

Keport  for  1893 ix 

Bureau  of  boiler  inspection  203 

Oil,  for  lubrication  of  engine 78 

Open  air  condenser  denned 146 

Ordinates ;  how  to  measure  easily 124 

Overstraining  of  steam  boilers 84 

Oxygen  in  steam 60 

Petroleum,  Ibs.  of  water  evaporated  from  and  at  212° 50 

Units  of  heat  of  combustion 50 

Physical  properties  of  steam 59 

Pipes,  how  to  cure  cracking  and  pounding 86 

Pine  rule  for  approximate  size 114 

Covering;  importance  of 158 

Threads 87 

Piping  of  a  mill  or  factory 156 

Piping,  first  thing  to  be  examined 158 

Pitch  line  of  rivet  work < 54 

Planimeter :  description  of 125 

Plates  of  boilers :  thickness  of 55 

Points  (4)  shown  by  an  indicator 1-22 

Poles  of  permanent  or  electro  magnets 131 

**  Pop  "  safety  valve ;  definition  of 90 

Ports;  steam;  definition 76 

Portable  engines 65 

Pressure  allowed  by  inspectors 56 

Initial,  of  steam 62 

Mean  effective,  how  to  find 79 

Terminal,  of  steam 63 

Prevention  of  emoke 160 

Priming  of  steam  boiler 140 

Proportion;  ruleof 170 

Pumps ;  description  of  different 105 

Action  of,  described 106-107 

Double  and  single  acting 107 

How  to  set  up  and  order 110 

Pistons;  area  of 112 

Steam  and  water  ends  of  a. 107 

That  leak Ill 

Treatment  of,  in  cold  weather 110 

Valves;  size  and  lift 108,115 

Questions  and  answers  relating  to 107 

Pump  and  in jector ;  difference  between 117 

Pumping  engines 

ladruple  expansion  engines 

lalifications  for  boiler  plates 

mlifications  (3)  necessary  to  secure  engineer's  license 

lestiona  (elementary)  by  the  examining  engineer , 

i  jna  And  answers  relating  to  boiler  braces  and  stays 


218  HAWKINS*  AIDS. 

Questions  and  answers  relating  to  Circulation  of  water  in  boilers  46 

Combustion  of  coal 48 

Construction  and  strength  of 

steam  boilers 52 

Electricity  and  electric  ma- 
chines   127 

Engine  and  boiler  fittings  —  83 
Expansion  and  contraction  of 

steam  boilers 32 

Firing 43 

Gravity  and  strength  of  ma- 
terials   134 

Heat  and  work 151 

Heating  and  ventilation 157 

Incrustation  and  scale 35 

Indicator 121 

Materials  for  bo  i  lers 22 

Physical  properties  of  steam.  59 

Pumps 107 

Refrigeration 143 

Safety  valve 89 

Smoke  prevention 160 

Steam  B  oiler 38 

Steam  engine 67 

Steam  injector 117 

Reaumur  thermometer,  scale 153 

Reducing  valve 85 

Refrigerant,  denned 142 

Refrigerate,  denned 142 

Refrigerating  machine 142 

Refrigeration ;  questions  and  answers  relating  to 143 

Direct  and  expansion  systems 144 

Regularity  of  speed 69 

Regulations  relating  to  marine  engineers 186 

Relief  valve 84 

Repairs  to  braces,  how  best  made 33 

Repellant  property  in  steam 63 

Report  of  Chief  Inspectors,  New  York  and  Brooklyn 200 

Results  obtained  from  diagram 123 

Rivet  holes ;  pitch  of    55 

Location  of 54 

Riveting;  kinds  of 52 

Rivets,  size  used  in  joining  sheets 53 

Rotary  engines 65 

Rule  for  ascertaining  number  and  size  of  stays  needed 33 

Calculating  power  of  steam  engine T9 

Calculating  strain  on  boiler  stays 33 

Capacity  of  boiler 116 

Capacity  of  water  cylinder 118 

Estimating  H.  P.  of  steam  boiler 140 

Figuring  safety  valves 92-97 

Finding  water  capacity  of  horizontal  steam  boiler 116 

Find  jig  capacity  of  pump  per  hour 113 

Finding  the  specif! c  gravities  of  solids ' ! .' .' .' ....'.'. '. '. '. .' .' .' .' '.  136 

Finding  the  total  heat  of  steam 102 

Finding  water  pumped  in  one  minute 113 

Reverse  motion  of  a  slide  valve  engine 75 

Size  of  pipe  for  steam. U4 

Rule  of  Proportion,  and  examples 171 

Three UO 


INDEX.  219 


Rulesfor  Firing 45 

Setting  up  a  steam  pump 116 

Size  of  safety  valve 91 

(U.  S.) ;  setting  safety  valves 182 

Rusted  spots  in  pipe ;  how  to  treat 86 

Safety  ;  factor  of,  for  fittings 86 

Safety  valve ;  Government  rules  for  the 182 

Danger  of  sticking 89 

Definition  of  a 89 

Location  and  size 90 

Safety  valve  Problems ;  how  to  solve  arithmetically 94 

Rules  for  size  of 91 

Salinometer,  defined 136 

Salt,  amount  in  sea- water 13t> 

Sand ;  specific  gravity  of 137 

Saturated  steam  59 

Heat  of 102 

Table  of  properti  «  of 98  99 

Scale;  different  kinds  of  boiler 35 

Scum-cock ;  action  of 36 

Seam ;  strength  of  riveted 56 

Second  assistant  engineers 188 

Setting-  a  pump  valve ;  rules  for 110 

Shearing  strength,  definition  of 22 

Signs,  arithmetical 165 

Silver,  specific  gravity  of 137 

Single-acting  engines 64 

Single-acting  pump 107 

Single  riveting 52 

Slide  valve,  defined 173 

Duties  of 73 

Engine ;  to  reverse  motion  of 79 

To  test  for  leaks 77 

Slippage , 114 

Smoke  ( The),  problem 160 

Solid-brace 30 

Soot,  effect  on  the  interior  of  boilers 36 

South  pole  of  electro-magnet 131 

Special  report  of  N.  Y.  Bureau 203 

Specific  heat,  definition  and  table 153 

Specific  gravity,  table 137 

Speed  of  escaping  steam  and  water 118 

Speed ;  regularity  of 70 

Spring ;  number  of  an  indicator 122 

Standard  of  cold  production 143 

Starting  an  engine 78 

Stationary  boilers ;  kinds  of 38 

Engines 65 

Stays ;  boiler 190 

Riveting  of  gusset  stays 34 

Steam ;  Boilers,  description 21 

Boiler ;  horizontal  tubular 38 

"  Breathing  "of 34 

Cause  of  explosion 41 

Effect  of  heat  on  strength  of 58 

Fixtures ;  list  of 83 

Fulcring 53 

Horse  power  of  ;  rule 140 

How  to  calculate  strength  of ,  with  example 57 

How  to  calculate  the  force  of  expansion  and  con- 
traction,  , ,»,.  28 


HAWKINS1  AIDS. 


Steam  Boiler ;  How  to  prepare  for  inspection 198 

Inspection  ;  N.  Y.  City  report 203 

Inspection ;  Brooklyn,  N.  Y.,  report 200 

Laws  relating  to  the  inspection  of 197 

Locomotive 40 

Marine 40 

Method  of  testing       54 

Overs t raining  of 34 

Principal  kinds 38 

Questions  and  answers  relating  to 52 

Stationary 38 

To  calculate  strength  of  seam 56 

Tube  plate  of 55 

Water  tube ...  39 

Steam ;  absolute  piessure  of 62 

Dead 59 

Dry 59 

Dry ;  as  a  conductor 104 

Expansion  under  pressure 60 

Gain  in  expansion , . . .   104 

Heating ;  Questions  and  answers  relating  to 157 

Heating  and  ventilation 155 

How  to  generate,  at  212°  F 102 

Invisibility  of 50 

Live 59 

Of  what  formed -.   .  121 

Physical  properties  of 59 

Repellant  quality  of  particles  of 63 

Saturated 59 

Saturated ;  Tables 98-99 

Superheated .  •  61 

Total  heat  of 102 

Weight  of 61 

Wet , 62 

Wire  drawing  of 63 

Steam-end  of  a  pump 107 

Engine..  . 64 

Engines ;  questions  and  answers 67 

Generators,  principal  kinds 38 

Injectors  ;  questions  and  answers  relating  to 117 

Jacket 104 

Line 121 

Pipe  covering ;  importance  of 158 

Pipe ;  how  to  estimate  the  safe  working  pressure 86 

Pipe ;  tensile  strength  of 87 

Pipe ;  how  to  estimate  the  diameter  of 86 

Pipe ;  how  to  estimate  the  size  of 114 

Pipe ;  Threads  of 87 

Pumps ;  direct  acting Ill 

Valves ;  how  to  connect 86 

Steamer  "  Northwest,"  description  of  engines 81 

Steel,  definition 25 

Difference  between,  and  iron. 25 

Specific  heat  of -> 153 

Specific  gravity  of 137 

Tensile  strength  of 25 

(Strain  and  stress  defined 135 

Strength  of  riveted  seam 56 

Steam  boilers 52 

Stress  and  strain  defined ; 135 

Stress  carried  by  boiler  stays,  example 83 


INDEX.  221 


Stuffing-box,  definition 76 

Submerged  condenser,  defined 146 

Subtraction  of  decimals 168 

Suction  chamber 1 10 

Suction  lift  of  a  pump 108 

Suction  pipes,  what  they  should  be  provided  with 111 

Sulphur;  specific  gravity  of 137 

Summary  of  arithmetic 166 

Switch  ;  definition  of  a 132 

Table  of  heat  of  combustion 60 

Mean  pressures  when  cutting  off 80 

Number  of  indicator  spring 123 

Properties  of  saturated  steam 98-99 

Specific  heat  153 

Specific  gravities 137 

Taking  charge  of  a  new  engine 88 

Tensile  strength  defined '. . . .  135 

Testing  boilers  ;  method  of 54 

Thermometer  ;  Centigrade,  description 152 

Description..   152 

Fahrenheit's 152 

Thimbles  for  boilers 83 

Third  assistant  engineers 189 

Three;  Rule  of 170 

Three-way  cock 85 

Throttle  valve 85 

Throttling  engines  68 

Through  braces 30 

Time  ;  unit  of.  154 

Tin,  specific  gravity 137 

Tortional  strength 135 

Total  heat  of  steam 102 

' '  Tough ' '  metal 23 

Transverse  strength  defined 135 

Triple  expansion  engines 81 

Tube  plate,  defined 55 

T.  U.  (thermal  unit) 108 

Unit  of  arithmetical  calculations 154 

Heat 151,154 

Pressure 154 

Time 154 

Work 154 

U.  S.  Government  rules  for  the  safety  valve 182 

Vacuum .  73 

Valve  ;  definition  of  a  84, 108 

Valves  of  Corliss  engines  ;  how  to  set 174 

Valve ;  relief,  back  pressure,  ball,  three-way,  cock,  check,  throt- 
tle, reducing,  etc 85 

Valve  spindle 90 

Ventilation  ;  heating  and  155 

Latest  idea  relating  to 159 

Questions  and  answers  relating  to 157 

Water  and  steam,  as  shown  by  diagram 124 

Cohesion  of 63 

Composition  of 116 

Circulation  in  boilers 47 

Cylinder  ;  capacity  of 113 

End  of  a  pump 107 

Gauges 42 

In  the  cylinder  ;  effect  of 74 

Specific  heat  of 153 


222  INDEX. 


Water  Standard  for  specific  gravity 134 

Tube  boilers,  good  and  bad  points 39 

Weakness  in  boilers ;  cause  of 41 

Weight  for  given  safety  valve  to  blow  at  given  pressure 182 

Weight ;  relative,  of  steam,  water  and  air 61 

Weights ;  measures  and 154 

Weldable  metal 23 

Wet  steam .  <M 

Wiredrawing •  63 

Wood,  Ibs.  of  water  evaporated  from  and  at  212° ^ 

Units  of  heat  of  combustion ,°X 

Work;  heat  and    150 

Unit  of Iff 

Units  of ,  as  units  of  heat 161 


Hawkins* 

Educational 

Works. 


LIST. 

I. 
Hawkins'  Self-Help  Mechanical  Drawing,  price  post-paid,    $2.00 

(For  Home  Study.) 
11. 

Hawkins*  New  Catechism  of  Electricity,  price  post-paid,      2.00 

III. 

Hawkins'  Aids  to  Engineers'  Examinations,  price  post- 
paid,   --.----•      2.00 

(With  Questions  and  Answers.) 

IV. 
Hawkins*  Maxims  and  Instructions  for  the  Boiler  Room, 

price  post-paid, •      2.00 

V. 

Hawkins'  Hand  Book  of  Calculations  for  Engineers,  price 

post-paid,      ....  .  2.00 

VI. 
Hawkins*  New  Catechism  of  the  Steam  Engine,  price 

post-paid, 2.00 

VII. 
Hawkins*  Indicator  Catechism  (a  practical  treatise) ,  price 

post-paid,      -  1.00 


Each  volume  is  provided  with  a  carefully  arranged  refer- 
ence index,  which  places  at  ready  command  the  information 
contained  in  the  book  upon  any  special  subject  upon  which 
immediate  help  is  needed. 


Hawkins'  Self-Help 

Mechanical  Drawing. 
Price,   $2. 


This  volume  contains  320  pages,  300  illustrations, 
diagrams  and  suggestive  sketches;  it  is  attractively 
and  strongly  bound  in  green  cloth,  with  full-gold 
edges  and  titles,  making  a  handsome  book,  7x10 
inches,  for  the  library,  for  study  and  ready  reference. 

It  is  superfluous  for  the  publishers  to  say  aught 
concerning  the  importance  of  knowing  how  to  draw, 
and  the  utility  of  draughting  in  industrial  pursuits  ; 
but  the  fact  cannot  be  too  frequently  reiterated  that 
the  education  of  the  mechanic  is  incomplete  without 
a  knowledge  of  drawing. 


CONTENTS. 


The  work  has  been  carefully  arranged  according 
to  the  fundamental  principles  of  the  art  of  drawing, 
each  theme  being  separately  treated,  and  many 
examples  given  for  practice.  A  list  of  the  subjects 
are  given  below,  all  of  which  are  plainly  described 
and  illustrated. 

Chalk  Work. 

Preliminary  Terms  and  Definitions. 
Freehand  Dra^ving. 

Geometrical  Drawing. 

Drawing  Materials  and  Instruments* 

Mechanical  Drawing. 
Penciling. 

Projection. 

"  Inking  in  "  Draivings. 
Lettering  Drawings. 

Dimensioning  Drawings. 

Shading  Drawings. 
Section  Lining  and  Colors. 
Reproducing  Drawings. 
Drawing  Office  Rules. 
Gearing. 

Designing  Gears. 

Working  Drawings. 
Reading  Working  Drawings. 

Patent  Office  Rules  for  Drawings. 
Useful  Hints  and  Points* 
Linear  Perspective. 
Useful  Tables. 

Personal,  by  the  Editor. 

The  practical  instructions  given  in  this  volume 
are  in  helpful  language,  such  as  a  teacher  would  use, 
and  it  is  to  be  hoped  that  the  book  will  serve,  at 
least,  as  a  stepping  stone  toward  a  thorough  mastery 
of  the  draughtsman's  art. 


New 
Catechism 

of 
Electricity. 

A 

Practical 

Treatise 

Price,  $2 


This  volume  contains  550  pages  of  valuable  informa- 
tion, 300  diagrams  and  illustrations,  handsomely 
bound  in  heavy  red  leather,  with  gold  edges,  making 
a  handy  pocket  companion,  replete  with  invaluable 
knowledge;  size  4^  x  6>£  inches. 

This  book  has  been  issued  in  response  to  a  real 
demand  for  a  plain  and  practical  treatise  on  the  care 
and  management  of  electrical  plants  and  apparatus — 
a  book  to  aid  the  average  man,  rather  than  the  invent- 
or or  experimenter  in  this  all-alive  matter. 

Hence  the  work  will  be  found  to  be  most  complete 
in  this  particular  direction,  containing  all  the  (book) 
information  necessary  for  an  experienced  man  to  take 
charge  of  a  dynamo  or  plant  of  any  size. 

So  important  is  the  subject  matter  of  this  admirable 
work  that  there  is  only  one  time  to  order  it  and  that  is 
NOW. 


CONTENTS. 


The  Dynamo;  Conductors  and  Non-Conductors; 
Symbols,  abbreviations  and  definitions  relating  to 
electricity;  Parts  of  the  Dynamo;  The  Motor;  The 
Care  and  Management  of  the  Dynamo  and  Motor 

Electric  Lighting;  Wiring;  The  rules  and  require- 
ments of  the  National  Board  of  Underwriters  in  full; 
Electrical  Measurements. 

The  Electric  Railway;  Line  Work;  Instruction  and 
Cautions  for  Linemen  and  the  Dynamo  Room  ;  Storage 
Batteries;  Care  and  Management  of  the  Street  Caf 
Motor;  Electro  Plating. 

The  Telephone  and  Telegraph ;  The  Electric  Eleva- 
tor; Accidents  and  Emergencies,  etc.,  etc. 

The  full  one-third  part  of  the  whole  work  has  been 
devoted  to  the  explanation  and  illustrations  of  the 
dynamo,  and  particular  directions  relating  to  its  care 
and  management; — all  the  directions  are  given  in  the 
simplest  and  most  kindly  way  to  assist  rather  than 
confuse  the  learner.  The  names  of  the  various  parts 
of  the  machine  are  also  given  with  pictorial  illustra- 
tions of  the  same. 

In  the  Catechism  no  less  than  25  full  page  illustra- 
tions have  been  given  of  the  various  dynamo  machines 
made  in  different  parts  of  the  country,  and  an  equal 
number  of  part  page  illustrations. 


Questions 

and 
Answers 

for 

Engineers. 
Price,  $2. 


This  volume  has  over  200  pages  of  practical  "pointers" 
showing  the  path  of  advancement,  so  much  desired  by  aspiring 
engineers  and  firemen.  It  is  printed  on  excellent  paper  and 
handsomely  bound  in  heavy  red  leather,  with  gold  title  and 
edges.  It  is  strongly  bound  for  continuous  study  ;  the  size  is 

5*7X. 

The  work  is  a  most  important  aid  to  all  engineers,  and 
is  undoubtedly  the  most  helpful  ever  issued  relating  to  a  safe 
and  sure  preparation  for  examination. 

It  presents  in  a  condensed  form  the  most  approved  prac- 
tice in  the  care  and  management  of  Steam  Boilers,  Engines, 
Pumps,  Electrical  and  Refrigerating  Machines. 

On  the  following  page  is  a  list  of  its   "  helpful  " 


CONTENTS. 


This  book  embraces  information  not  elsewhere  obtainable. 

It  tells  exactly  what  an  engineer  will  have  to  go  through 
in  getting  a  license,  with  much  kindly  and  helpful  advice  to 
the  applicant  for  a  license. 

It  contains  the  annual  report  of  the  superintendents  of 
"Steam  Boiler  Inspection  and  Certification  of  Engineers"  foi 
the  cities  of  New  York  and  Brooklyn. 

It  contains  various  rules,  regulations  and  laws  of  cities 
for  the  examination  of  boilers  and  the  licensing  of  engineers. 

It  contains  the  laws  and  regulations  of  the  United  States 
for  the  examination  and  grading  of  all  marine  engineers. 

It  gives  a  short  chapter  on  the  "Key  to  Success"  in 
obtaining  knowledge  necessary  for  advancement  in  engineering. 
This  is  very  important. 

The  book  gives  the  underlying  principles  of  steam  engineer- 
ing in  plain  language,  with  sample  questions  and  answers 
likely  to  be  asked  by  the  examiner. 

It  gives  a  few  plain  rules  of  arithmetic  with  examples  of 
how  to  work  the  problems  relating  to  the  safety  valve,  streng  h 
of  boilers  and  horse  power  of  the  Steam  Engine  and  Steam 
Boiler. 

The  main  subjects  treated,  upon  which  are  given  detailed 
information  with  questions  and  answers,  are  as  follows: — 
The  Steam  Boiler,  Boiler  Braces,  Incrustation  and  Scale, 
Firing  of  Steam  Boilers,  Water  Circulation  in  Boilers,  Con- 
struction and  Strength  of  Boilers,  The  Steam  Engine,  Engine 
and  Boiler  Fittings,  Pumps,  The  Injector,  Electricity  and 
Electric  Machines,  Steam  Heating,  Refrigeration,  Valve 
Setting,  etc. ,  etq. 


Maxims 

and 
Instructions 

for  the 

Boiler  Room 

Price,  $2. 


This  is,  of  all  the  Hawkins  books,  perhaps  the 
most  useful  to  the  Engineer-in-charge,  to  the  Fireman, 
to  the  Steam  user  or  owner,  and  to  the  student  of 
Steam  Engineering. 

It  is  uniform  in  binding  and  size  with  "  Calcula- 
tions for  Engineers  "  and  the  "New  Catechism  of  the 
Steam  Engine";  the  size  is  6x8^  inches,  i^  inches 
thick;  weight  2  Ibs  ;  it  is  bound  in  green  silk  cloth, 
gilt  top  and  titles  in  gold;  it  has  331  pages  with  185 
diagrams  and  illustrations. 

See  next  page  for  further  particulars  relating  to 
the  practical  subjects  embraced  in  this  valuable 
volume.  * 


CONTENTS. 

Materials;  Evaporation;  Fire  Irons  and  Tools; 
Firing  of  Steam  Boilers;  Points  relating  to  Fuels; 
Foaming ;  Chapter  of  Don'ts ;  Full  descriptions  of  the 
Locomotive,  Upright,  Water  Tube,  Horizontal,  and 
Marine  Steam  Boilers;  Parts  of  a  Boiler;  Various 
Specifications  for  Construction  of  a  Boiler;  Riveting; 
Bracing;  Various  Repairs;  Grate  Bars;  Boiler 
Cleaners;  Boiler  Scales;  Boiler  Tests;  Scumming; 
Chemical  Terms;  Inspection  of  Boilers;  Mechanical 
Stokers;  Pumping  Machinery;  Feed  Water  Heaters; 
Steam  Heating;  Plumbing;  Safety  Valve  Rules. 

And  many  hundreds  of  other  valuable  pointers 
for  Steam  Users,  Superintendents,  Engineers,  etc. 

No  Engineer,  Fireman  or  Steam  User  can  afford 
to  be  without  this  valuable  book,  as  it  contains  the 
pith  and  vital  "  points  "  of  economical  and  safe  steam 
production. 

The  plan  followed  in  this  work  is  the  same  as 
that  so  generally  approved  in  "Calculations";  it 
proceeds  from  the  most  simple  rules  and  maxims  to 
the  highest  problems;  it  is  both  a  book  of  instruction 
and  reference.  The  carefully  prepared  Index  con- 
tains nearly  one  thousand  references,  thus  making  it 
almost  a  dictionary  of  terms. 


DBOOK 
OF 

;ULATIO|; 

FOR 

NEERSI 


Hand  Book 

of 
Calculations 

for 
Engineers. 

Price  $2. 


f  The  work  comprises  the  elements  of  Arithmetic,  Mensura- 
tion, Geometry,  Mechanical  Philosophy,  with  copious  notes, 
•explanations  and  help  rules  useful  to  an  Engineer. 

And  for  reference,  tables  of  squares  and  cubes,  square  and 
cube  roots,  circumference  and  areas  of  circles,  tables  of  weights 
of  metals  and  pipes,  tables  of  pressures  of  steam,  etc.,  etc. 

This  is  a  work  of  instruction  and  reference  relating  to  the 
steam  engine,  the  steam  boiler,  etc  ,  and  has  been  said  to  con- 
tain every  calculation,  rule  and  table  necessary  to  be  known  by 
the  Engineer,  Fireman  and  steam  user. 

It  is  thus  a'_  complete  course  in  Mathematics  for  the  Engineer 
and  steam  user;  all  calculations  are  in  plain  arithmetical 
figures,  so  the  average  man  need  not  be  confused  by  the  inser- 
tion of  the  terms,  symbols  and  characters  to  be  found  in  works 
of  "  higher  mathematics,"  so-called,  yet  the  book  is  a  complete 
treatise. 

It  is  bound  uniform  with  the  "  New  Catechism  of  the  Steam 
Engine"  and  the  "Instructions  for  the  Boiler  Room"  (size 
6  x  8#  inches,  weight  2  Ibs. );  in  green  silk  cloth  ;  printed  on 
heavy,  fine  surface  paper  ;  gold  titles,  gilt  top  ;  with  330  pages 
and  150  illustrations, 


CONTENTS. 


Mechanical  Powers;  Natural  or  Mechanical  Philos- 
ophy, Strength  of  Materials;  Mensuration;  Arith- 
metic; Description  of  Algebra  and  Geometry;  Tables 
of  Weights,  Measures,  Strength  of  Rope  and  Chains, 
Pressures  of  Water,  Diameter  of  Pipes,  etc.  ;  The 
Indicator,  How  to  Compute;  The  Safety  Valve,  How 
to  Figure;  The  Steam  Boiler;  The  Steam  Pump; 
Horse  Dowers,  How  to  Figure  for  Engines  and 
Boilers;  Steam,  What  It  Is,  etc.;  Index  and  Useful 
Definitions,, 


"  I  am  pleased  with  the  work  ;  it  is  of 
value  to  me.  I  have  charge  of  a  Harris  - 
Corliss  engine  doing  680  H.  P.  at  Slater's 
Cotton  Mills." — CYRUS  BUCKUN,  Paw- 
tucket,  R.  I. 

"I  think  it  the  best  T  ever  saw, .and  I 
thank  the  day  I  saw  it  advertised." — 
JNO.  C.  ROBINSON,  Adams,  Mass. 

•'The  Hand  Book  is  worth  its  weight  in 
dollars  to  any  engineer  with  common 
sense."— J AS.  C.  TEMPLE,  Eng.,  Spring- 
field, 111. 


New 
Catechism 

of  the 

Steam 
Engine. 

Price,  $2. 


This  is  a  rarely  fine  book,  handsomely  bound  in 
green  silk  cloth,  gilt  top,  titles  in  gold;  440  pages; 
325  illustrations;  size  6x8^  inches,  i^  inches  thick; 
weight  2  IbSo  It  is  bound  uniform  in  style  and  size 
with  the  "Hand  Book  of  Calculations"  and  "Maxims 
and  Instructions  for  the  Boiler  Room.'* 

This  will  prove  a  valuable  book  both  for  study  and 
reference,  being  finely  illustrated  and  indexed. 

This  work  is  gotten  up  to  fill  a  long-felt  need  for  a 
practical  book.  It  gives  directions  for  running  the 
various  types  of  steam  engines  that  are  to-day  in  the 
market.  A  list  of  subjects  which  are  fully  yet  con- 
cisely discussed  are  found  on  the  next  page. 


CONTENTS. 


The  subject  matter  of  the  New  Catechism  of  the 
Steam  Engine  is  not  arranged  in  chapters,  but  accord- 
ing to  the  more  natural  order  best  designed  to  explain 
at  greater  or  less  length  the  different  themes  discussed. 
The  following  are  the  leading  divisions  of  the  480 
pages  of  the  book: 

Introduction;  The  Steam  Engine;  Historical  Facts 
Relating  to  the  Steam  Engine;  Engine  Foundations; 
The  Steam  Piston;  Connecting  Rods;  Eccentric; 
Governor;  Materials;  Workmanship;  Care  and 
Management;  Lining  up  a  Horizontal  or  Vertical 
Engine;  Lining  Shafting;  Valve  Setting;  Condensers; 
Steam  Separators ;  Air,  Gas  and  Compressing  Engines ; 
Compounding;  Arithmetic  of  the  Steam  Engine; 
Theory  of  the  Steam  Engine ;  Construction. 

There  is  also  a  description  of  numerous  types  of 
the  engines  now  in  operation,  such  as  the  Corliss, 
Westinghouse,  etc. 

The  book  also  treats  generously  upon  the  Marine, 
Locomotive  and  Gas  Engines. 


Indicator 
Catechism 

a 

Practical 
Treatise. 
Price,  $1. 


This  is  a  ne.v  book  on  an  important  subject.  It  is  designed 
to  thoroughly  instruct  the  buyer  upon  the  practical  use  of  the 
Indicator,  the  Planimeter,  the  Pantagraph,  Reducing  Motions, 
etc.  It  contains  nearly  200  pages  with  1 15  valuable  illustrations 
and  diagrams,  with  questions  and  answers. 

CONTENTS.— Preparing  Indicator  for  Use;  Reducing 
Motions  ;  Piping  up  Indicator  ;  Taking  Indicator  Cards  ;  The 
Diagram ;  Figuring  Steam  Consumption  by  the  Diagram  • 
Revolution  Counters;  Examples  of  Diagrams;  Description 
of  Indicators  ;  Measuring  Diagram  by  Ordinates  ;  Planimeters  ; 
Pantagraphs,  Tables,  etc. 

The  book  is  handsomely  bound  in  silk  (red)  cloth,  gilt  edges, 
gold  titles  ;  it  is  5^  x  8X  inches  and  weighs  r#  Ibs. 


Books  will  be  sent  post- 
paid to  any  address  on 
receipt  of  price.  ^ 


Send  remittances  by  Post 
Office  or  Express  Money 
Orders  payable  to  our 
order. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
BERKELEY 


Return  to  desk  from  which  borrowed. 
This  book  is  DUE  on  the  last  date  stamped  below. 
ENGINEERING  i  IRRARV 


W  1QRC 


MAR 


APR  2  8  195 


V 


LD  21-100?n-9,'47(A5702sl6)476 


24174 


838785 


Ht7 


THE  UNIVERSITY  OF  CALIFORNIA  LIBRARY 


